From 4bd46579068977ef12efc8ac8cc65ed73c8be747 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 11:24:27 +0100
Subject: [PATCH 01/46] Add kotlin plugin

---
 build.gradle | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/build.gradle b/build.gradle
index 56730fd..577c2aa 100644
--- a/build.gradle
+++ b/build.gradle
@@ -19,6 +19,8 @@ buildscript {
 
 plugins {
     id 'ru.vyarus.animalsniffer' version '1.5.3'
+    id 'org.jetbrains.kotlin.jvm' version "1.8.10"
+    id 'com.diffplug.spotless' version '6.22.0' apply false
 }
 
 apply from: 'version.gradle'
@@ -29,6 +31,8 @@ allprojects {
     apply plugin: 'eclipse'
     apply plugin: 'jacoco'
     apply plugin: 'checkstyle'
+    apply plugin: 'kotlin'
+    apply plugin: 'com.diffplug.spotless'
 
     // For non-cli modules enable android api compatibility check
     if (it.name.equals('sop-java')) {
@@ -53,6 +57,12 @@ allprojects {
         toolVersion = '8.18'
     }
 
+    spotless {
+        kotlin {
+            ktfmt().dropboxStyle()
+        }
+    }
+
     group 'org.pgpainless'
     description = "Stateless OpenPGP Protocol API for Java"
     version = shortVersion
@@ -69,6 +79,13 @@ allprojects {
         reproducibleFileOrder = true
     }
 
+    // Compatibility of default implementations in kotlin interfaces with Java implementations.
+    tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
+        kotlinOptions {
+            freeCompilerArgs += ["-Xjvm-default=all-compatibility"]
+        }
+    }
+
     project.ext {
         rootConfigDir = new File(rootDir, 'config')
         gitCommit = getGitCommit()

From 0f5270c28da4f63c364a9f1d2561355a0f2f6fa9 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 11:24:36 +0100
Subject: [PATCH 02/46] Kotlin conversion: ByteArrayAndResult

---
 .../src/main/java/sop/ByteArrayAndResult.java | 50 -------------------
 .../src/main/kotlin/sop/ByteArrayAndResult.kt | 43 ++++++++++++++++
 2 files changed, 43 insertions(+), 50 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/ByteArrayAndResult.java
 create mode 100644 sop-java/src/main/kotlin/sop/ByteArrayAndResult.kt

diff --git a/sop-java/src/main/java/sop/ByteArrayAndResult.java b/sop-java/src/main/java/sop/ByteArrayAndResult.java
deleted file mode 100644
index fd2b39a..0000000
--- a/sop-java/src/main/java/sop/ByteArrayAndResult.java
+++ /dev/null
@@ -1,50 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import java.io.ByteArrayInputStream;
-import java.io.InputStream;
-
-/**
- * Tuple of a byte array and associated result object.
- * @param <T> type of result
- */
-public class ByteArrayAndResult<T> {
-
-    private final byte[] bytes;
-    private final T result;
-
-    public ByteArrayAndResult(byte[] bytes, T result) {
-        this.bytes = bytes;
-        this.result = result;
-    }
-
-    /**
-     * Return the byte array part.
-     *
-     * @return bytes
-     */
-    public byte[] getBytes() {
-        return bytes;
-    }
-
-    /**
-     * Return the result part.
-     *
-     * @return result
-     */
-    public T getResult() {
-        return result;
-    }
-
-    /**
-     * Return the byte array part as an {@link InputStream}.
-     *
-     * @return input stream
-     */
-    public InputStream getInputStream() {
-        return new ByteArrayInputStream(getBytes());
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/ByteArrayAndResult.kt b/sop-java/src/main/kotlin/sop/ByteArrayAndResult.kt
new file mode 100644
index 0000000..021a2d9
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/ByteArrayAndResult.kt
@@ -0,0 +1,43 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import java.io.InputStream
+
+/**
+ * Tuple of a [ByteArray] and associated result object.
+ *
+ * @param bytes byte array
+ * @param result result object
+ * @param <T> type of result
+ */
+data class ByteArrayAndResult<T>(val bytes: ByteArray, val result: T) {
+
+    /**
+     * [InputStream] returning the contents of [bytes].
+     *
+     * @return input stream
+     */
+    val inputStream: InputStream
+        get() = bytes.inputStream()
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as ByteArrayAndResult<*>
+
+        if (!bytes.contentEquals(other.bytes)) return false
+        if (result != other.result) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var hashCode = bytes.contentHashCode()
+        hashCode = 31 * hashCode + (result?.hashCode() ?: 0)
+        return hashCode
+    }
+}

From 567571cf6cbc657e6f4713dea38bda7f34eb63ac Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 11:33:15 +0100
Subject: [PATCH 03/46] Kotlin conversion: SessionKey

---
 sop-java/src/main/java/sop/SessionKey.java | 80 ----------------------
 sop-java/src/main/kotlin/sop/SessionKey.kt | 48 +++++++++++++
 2 files changed, 48 insertions(+), 80 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/SessionKey.java
 create mode 100644 sop-java/src/main/kotlin/sop/SessionKey.kt

diff --git a/sop-java/src/main/java/sop/SessionKey.java b/sop-java/src/main/java/sop/SessionKey.java
deleted file mode 100644
index 722666d..0000000
--- a/sop-java/src/main/java/sop/SessionKey.java
+++ /dev/null
@@ -1,80 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import java.util.Arrays;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
-import sop.util.HexUtil;
-
-public class SessionKey {
-
-    private static final Pattern PATTERN = Pattern.compile("^(\\d):([0-9A-F]+)$");
-
-    private final byte algorithm;
-    private final byte[] sessionKey;
-
-    public SessionKey(byte algorithm, byte[] sessionKey) {
-        this.algorithm = algorithm;
-        this.sessionKey = sessionKey;
-    }
-
-    /**
-     * Return the symmetric algorithm octet.
-     *
-     * @return algorithm id
-     */
-    public byte getAlgorithm() {
-        return algorithm;
-    }
-
-    /**
-     * Return the session key.
-     *
-     * @return session key
-     */
-    public byte[] getKey() {
-        return sessionKey;
-    }
-
-    @Override
-    public int hashCode() {
-        return getAlgorithm() * 17 + Arrays.hashCode(getKey());
-    }
-
-    @Override
-    public boolean equals(Object other) {
-        if (other == null) {
-            return false;
-        }
-        if (this == other) {
-            return true;
-        }
-        if (!(other instanceof SessionKey)) {
-            return false;
-        }
-
-        SessionKey otherKey = (SessionKey) other;
-        return getAlgorithm() == otherKey.getAlgorithm() && Arrays.equals(getKey(), otherKey.getKey());
-    }
-
-    public static SessionKey fromString(String string) {
-        string = string.trim().toUpperCase().replace("\n", "");
-        Matcher matcher = PATTERN.matcher(string);
-        if (!matcher.matches()) {
-            throw new IllegalArgumentException("Provided session key does not match expected format.");
-        }
-        byte algorithm = Byte.parseByte(matcher.group(1));
-        String key = matcher.group(2);
-
-        return new SessionKey(algorithm, HexUtil.hexToBytes(key));
-    }
-
-    @Override
-    public String toString() {
-        return Integer.toString(getAlgorithm()) + ':' + HexUtil.bytesToHex(sessionKey);
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/SessionKey.kt b/sop-java/src/main/kotlin/sop/SessionKey.kt
new file mode 100644
index 0000000..af230f3
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/SessionKey.kt
@@ -0,0 +1,48 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import sop.util.HexUtil
+
+/**
+ * Class representing a symmetric session key.
+ *
+ * @param algorithm symmetric key algorithm ID
+ * @param key [ByteArray] containing the session key
+ */
+data class SessionKey(val algorithm: Byte, val key: ByteArray) {
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as SessionKey
+
+        if (algorithm != other.algorithm) return false
+        if (!key.contentEquals(other.key)) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var hashCode = algorithm.toInt()
+        hashCode = 31 * hashCode + key.contentHashCode()
+        return hashCode
+    }
+
+    override fun toString(): String = "$algorithm:${HexUtil.bytesToHex(key)}"
+
+    companion object {
+
+        @JvmStatic private val PATTERN = "^(\\d):([0-9A-F]+)$".toPattern()
+
+        @JvmStatic
+        fun fromString(string: String): SessionKey {
+            val matcher = PATTERN.matcher(string.trim().uppercase().replace("\n", ""))
+            require(matcher.matches()) { "Provided session key does not match expected format." }
+            return SessionKey(matcher.group(1).toByte(), HexUtil.hexToBytes(matcher.group(2)))
+        }
+    }
+}

From 6c5c4b3d981aa62f28dfde36a2e56821d279620f Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 12:25:54 +0100
Subject: [PATCH 04/46] Kotlin conversion: Verification

---
 sop-java/src/main/java/sop/Verification.java | 222 -------------------
 sop-java/src/main/kotlin/sop/Verification.kt |  76 +++++++
 2 files changed, 76 insertions(+), 222 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/Verification.java
 create mode 100644 sop-java/src/main/kotlin/sop/Verification.kt

diff --git a/sop-java/src/main/java/sop/Verification.java b/sop-java/src/main/java/sop/Verification.java
deleted file mode 100644
index 140e23b..0000000
--- a/sop-java/src/main/java/sop/Verification.java
+++ /dev/null
@@ -1,222 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import sop.enums.SignatureMode;
-import sop.util.Optional;
-import sop.util.UTCUtil;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-import java.text.ParseException;
-import java.util.Date;
-
-/**
- * Class bundling information about a verified signature.
- */
-public class Verification {
-
-    private final Date creationTime;
-    private final String signingKeyFingerprint;
-    private final String signingCertFingerprint;
-    private final Optional<SignatureMode> signatureMode;
-    private final Optional<String> description;
-
-    private static final String MODE = "mode:";
-
-    /**
-     * Create a new {@link Verification} without mode and description.
-     *
-     * @param creationTime signature creation time
-     * @param signingKeyFingerprint fingerprint of the signing (sub-) key
-     * @param signingCertFingerprint fingerprint of the certificate
-     */
-    public Verification(@Nonnull Date creationTime,
-                        @Nonnull String signingKeyFingerprint,
-                        @Nonnull String signingCertFingerprint) {
-        this(creationTime, signingKeyFingerprint, signingCertFingerprint, Optional.ofEmpty(), Optional.ofEmpty());
-    }
-
-    /**
-     * Create a new {@link Verification}.
-     *
-     * @param creationTime signature creation time
-     * @param signingKeyFingerprint fingerprint of the signing (sub-) key
-     * @param signingCertFingerprint fingerprint of the certificate
-     * @param signatureMode signature mode (optional, may be <pre>null</pre>)
-     * @param description free-form description, e.g. <pre>certificate from dkg.asc</pre> (optional, may be <pre>null</pre>)
-     */
-    public Verification(@Nonnull Date creationTime,
-                        @Nonnull String signingKeyFingerprint,
-                        @Nonnull String signingCertFingerprint,
-                        @Nullable SignatureMode signatureMode,
-                        @Nullable String description) {
-        this(
-                creationTime,
-                signingKeyFingerprint,
-                signingCertFingerprint,
-                Optional.ofNullable(signatureMode),
-                Optional.ofNullable(nullSafeTrim(description))
-        );
-    }
-
-    private Verification(@Nonnull Date creationTime,
-                         @Nonnull String signingKeyFingerprint,
-                         @Nonnull String signingCertFingerprint,
-                         @Nonnull Optional<SignatureMode> signatureMode,
-                         @Nonnull Optional<String> description) {
-        this.creationTime = creationTime;
-        this.signingKeyFingerprint = signingKeyFingerprint;
-        this.signingCertFingerprint = signingCertFingerprint;
-        this.signatureMode = signatureMode;
-        this.description = description;
-    }
-
-    private static String nullSafeTrim(@Nullable String string) {
-        if (string == null) {
-            return null;
-        }
-        return string.trim();
-    }
-
-    @Nonnull
-    public static Verification fromString(@Nonnull String toString) {
-        String[] split = toString.trim().split(" ");
-        if (split.length < 3) {
-            throw new IllegalArgumentException("Verification must be of the format 'UTC-DATE OpenPGPFingerprint OpenPGPFingerprint [mode] [info]'");
-        }
-
-        if (split.length == 3) {
-            return new Verification(
-                    parseUTCDate(split[0]),         // timestamp
-                    split[1],                       // key FP
-                    split[2]                        // cert FP
-            );
-        }
-
-        SignatureMode mode = null;
-        int index = 3;
-        if (split[index].startsWith(MODE)) {
-            mode = SignatureMode.valueOf(split[3].substring(MODE.length()));
-            index++;
-        }
-
-        StringBuilder sb = new StringBuilder();
-        for (int i = index; i < split.length; i++) {
-            if (sb.length() != 0) {
-                sb.append(' ');
-            }
-            sb.append(split[i]);
-        }
-
-        return new Verification(
-                parseUTCDate(split[0]),                 // timestamp
-                split[1],                               // key FP
-                split[2],                               // cert FP
-                mode,                                   // signature mode
-                sb.length() != 0 ? sb.toString() : null // description
-        );
-    }
-
-    private static Date parseUTCDate(String utcFormatted) {
-        try {
-            return UTCUtil.parseUTCDate(utcFormatted);
-        } catch (ParseException e) {
-            throw new IllegalArgumentException("Malformed UTC timestamp.", e);
-        }
-    }
-
-    /**
-     * Return the signatures' creation time.
-     *
-     * @return signature creation time
-     */
-    @Nonnull
-    public Date getCreationTime() {
-        return creationTime;
-    }
-
-    /**
-     * Return the fingerprint of the signing (sub)key.
-     *
-     * @return signing key fingerprint
-     */
-    @Nonnull
-    public String getSigningKeyFingerprint() {
-        return signingKeyFingerprint;
-    }
-
-    /**
-     * Return the fingerprint fo the signing certificate.
-     *
-     * @return signing certificate fingerprint
-     */
-    @Nonnull
-    public String getSigningCertFingerprint() {
-        return signingCertFingerprint;
-    }
-
-    /**
-     * Return the mode of the signature.
-     * Optional, may return <pre>null</pre>.
-     *
-     * @return signature mode
-     */
-    @Nonnull
-    public Optional<SignatureMode> getSignatureMode() {
-        return signatureMode;
-    }
-
-    /**
-     * Return an optional description.
-     * Optional, may return <pre>null</pre>.
-     *
-     * @return description
-     */
-    @Nonnull
-    public Optional<String> getDescription() {
-        return description;
-    }
-
-    @Override
-    public String toString() {
-        StringBuilder sb = new StringBuilder()
-                .append(UTCUtil.formatUTCDate(getCreationTime()))
-                .append(' ')
-                .append(getSigningKeyFingerprint())
-                .append(' ')
-                .append(getSigningCertFingerprint());
-
-        if (signatureMode.isPresent()) {
-            sb.append(' ').append(MODE).append(signatureMode.get());
-        }
-
-        if (description.isPresent()) {
-            sb.append(' ').append(description.get());
-        }
-
-        return sb.toString();
-    }
-
-    @Override
-    public int hashCode() {
-        return toString().hashCode();
-    }
-
-    @Override
-    public boolean equals(Object obj) {
-        if (obj == null) {
-            return false;
-        }
-        if (this == obj) {
-            return true;
-        }
-        if (!(obj instanceof Verification)) {
-            return false;
-        }
-        Verification other = (Verification) obj;
-        return toString().equals(other.toString());
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/Verification.kt b/sop-java/src/main/kotlin/sop/Verification.kt
new file mode 100644
index 0000000..20401a9
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/Verification.kt
@@ -0,0 +1,76 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import java.text.ParseException
+import java.util.Date
+import sop.enums.SignatureMode
+import sop.util.Optional
+import sop.util.UTCUtil
+
+data class Verification(
+    val creationTime: Date,
+    val signingKeyFingerprint: String,
+    val signingCertFingerprint: String,
+    val signatureMode: Optional<SignatureMode>,
+    val description: Optional<String>
+) {
+    @JvmOverloads
+    constructor(
+        creationTime: Date,
+        signingKeyFingerprint: String,
+        signingCertFingerprint: String,
+        signatureMode: SignatureMode? = null,
+        description: String? = null
+    ) : this(
+        creationTime,
+        signingKeyFingerprint,
+        signingCertFingerprint,
+        Optional.ofNullable(signatureMode),
+        Optional.ofNullable(description?.trim()))
+
+    override fun toString(): String =
+        "${UTCUtil.formatUTCDate(creationTime)} $signingKeyFingerprint $signingCertFingerprint" +
+            (if (signatureMode.isPresent) " mode:${signatureMode.get()}" else "") +
+            (if (description.isPresent) " ${description.get()}" else "")
+
+    companion object {
+        @JvmStatic
+        fun fromString(string: String): Verification {
+            val split = string.trim().split(" ")
+            require(split.size >= 3) {
+                "Verification must be of the format 'UTC-DATE OpenPGPFingerprint OpenPGPFingerprint [mode] [info]'."
+            }
+            if (split.size == 3) {
+                return Verification(parseUTCDate(split[0]), split[1], split[2])
+            }
+
+            var index = 3
+            val mode =
+                if (split[3].startsWith("mode:")) {
+                    index += 1
+                    SignatureMode.valueOf(split[3].substring("mode:".length))
+                } else null
+
+            val description = split.subList(index, split.size).joinToString(" ").ifBlank { null }
+
+            return Verification(
+                parseUTCDate(split[0]),
+                split[1],
+                split[2],
+                Optional.ofNullable(mode),
+                Optional.ofNullable(description))
+        }
+
+        @JvmStatic
+        private fun parseUTCDate(string: String): Date {
+            return try {
+                UTCUtil.parseUTCDate(string)
+            } catch (e: ParseException) {
+                throw IllegalArgumentException("Malformed UTC timestamp.", e)
+            }
+        }
+    }
+}

From ef4b01c6bd73d74a3b3d203ec5da2a0228431f4e Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 12:42:13 +0100
Subject: [PATCH 05/46] Kotlin conversion: Profile

---
 sop-java/src/main/java/sop/Profile.java | 143 ------------------------
 sop-java/src/main/kotlin/sop/Profile.kt |  87 ++++++++++++++
 2 files changed, 87 insertions(+), 143 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/Profile.java
 create mode 100644 sop-java/src/main/kotlin/sop/Profile.kt

diff --git a/sop-java/src/main/java/sop/Profile.java b/sop-java/src/main/java/sop/Profile.java
deleted file mode 100644
index 4ea9e71..0000000
--- a/sop-java/src/main/java/sop/Profile.java
+++ /dev/null
@@ -1,143 +0,0 @@
-// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import sop.util.Optional;
-import sop.util.UTF8Util;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
-/**
- * Tuple class bundling a profile name and description.
- *
- * @see <a href="https://www.ietf.org/archive/id/draft-dkg-openpgp-stateless-cli-05.html#name-profile">
- *     SOP Spec - Profile</a>
- */
-public class Profile {
-
-    private final String name;
-    private final Optional<String> description;
-
-    /**
-     * Create a new {@link Profile} object.
-     * The {@link #toString()} representation MUST NOT exceed a length of 1000 bytes.
-     *
-     * @param name profile name
-     * @param description profile description
-     */
-    public Profile(@Nonnull String name, @Nullable String description) {
-        if (name.trim().isEmpty()) {
-            throw new IllegalArgumentException("Name cannot be empty.");
-        }
-        if (name.contains(":")) {
-            throw new IllegalArgumentException("Name cannot contain ':'.");
-        }
-        if (name.contains(" ") || name.contains("\n") || name.contains("\t") || name.contains("\r")) {
-            throw new IllegalArgumentException("Name cannot contain whitespace characters.");
-        }
-
-        this.name = name;
-
-        if (description == null) {
-            this.description = Optional.ofEmpty();
-        } else {
-            String trimmedDescription = description.trim();
-            if (trimmedDescription.isEmpty()) {
-                this.description = Optional.ofEmpty();
-            } else {
-                this.description = Optional.of(trimmedDescription);
-            }
-        }
-
-        if (exceeds1000CharLineLimit(this)) {
-            throw new IllegalArgumentException("The line representation of a profile MUST NOT exceed 1000 bytes.");
-        }
-    }
-
-    public Profile(String name) {
-        this(name, null);
-    }
-
-    /**
-     * Parse a {@link Profile} from its string representation.
-     *
-     * @param string string representation
-     * @return profile
-     */
-    public static Profile parse(String string) {
-        if (string.contains(": ")) {
-            // description after colon, e.g. "default: Use implementers recommendations."
-            String name = string.substring(0, string.indexOf(": "));
-            String description = string.substring(string.indexOf(": ") + 2);
-            return new Profile(name, description.trim());
-        }
-
-        if (string.endsWith(":")) {
-            // empty description, e.g. "default:"
-            return new Profile(string.substring(0, string.length() - 1));
-        }
-
-        // no description
-        return new Profile(string.trim());
-    }
-
-    /**
-     * Return the name (also known as identifier) of the profile.
-     * A profile name is a UTF-8 string that has no whitespace in it.
-     * Similar to OpenPGP Notation names, profile names are divided into two namespaces:
-     * The IETF namespace and the user namespace.
-     * A profile name in the user namespace ends with the <pre>@</pre> character (0x40) followed by a DNS domain name.
-     * A profile name in the IETF namespace does not have an <pre>@</pre> character.
-     * A profile name in the user space is owned and controlled by the owner of the domain in the suffix.
-     * A profile name in the IETF namespace that begins with the string <pre>rfc</pre> should have semantics that hew as
-     * closely as possible to the referenced RFC.
-     * Similarly, a profile name in the IETF namespace that begins with the string <pre>draft-</pre> should have
-     * semantics that hew as closely as possible to the referenced Internet Draft.
-     *
-     * @return name
-     */
-    @Nonnull
-    public String getName() {
-        return name;
-    }
-
-    /**
-     * Return a free-form description of the profile.
-     *
-     * @return description
-     */
-    @Nonnull
-    public Optional<String> getDescription() {
-        return description;
-    }
-
-    public boolean hasDescription() {
-        return description.isPresent();
-    }
-
-    /**
-     * Convert the profile into a String for displaying.
-     *
-     * @return string
-     */
-    @Override
-    public String toString() {
-        if (getDescription().isEmpty()) {
-            return getName();
-        }
-        return getName() + ": " + getDescription().get();
-    }
-
-    /**
-     * Test if the string representation of the profile exceeds the limit of 1000 bytes length.
-     * @param profile profile
-     * @return <pre>true</pre> if the profile exceeds 1000 bytes, <pre>false</pre> otherwise.
-     */
-    private static boolean exceeds1000CharLineLimit(Profile profile) {
-        String line = profile.toString();
-        return line.getBytes(UTF8Util.UTF8).length > 1000;
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/Profile.kt b/sop-java/src/main/kotlin/sop/Profile.kt
new file mode 100644
index 0000000..2125c57
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/Profile.kt
@@ -0,0 +1,87 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import sop.util.Optional
+import sop.util.UTF8Util
+
+/**
+ * Tuple class bundling a profile name and description.
+ *
+ * @param name profile name. A profile name is a UTF-8 string that has no whitespace in it. Similar
+ *   to OpenPGP Notation names, profile names are divided into two namespaces: The IETF namespace
+ *   and the user namespace. A profile name in the user namespace ends with the `@` character (0x40)
+ *   followed by a DNS domain name. A profile name in the IETF namespace does not have an `@`
+ *   character. A profile name in the user space is owned and controlled by the owner of the domain
+ *   in the suffix. A profile name in the IETF namespace that begins with the string `rfc` should
+ *   have semantics that hew as closely as possible to the referenced RFC. Similarly, a profile name
+ *   in the IETF namespace that begins with the string `draft-` should have semantics that hew as
+ *   closely as possible to the referenced Internet Draft.
+ * @param description a free-form description of the profile.
+ * @see <a
+ *   href="https://www.ietf.org/archive/id/draft-dkg-openpgp-stateless-cli-05.html#name-profile">
+ *   SOP Spec - Profile</a>
+ */
+data class Profile(val name: String, val description: Optional<String>) {
+
+    @JvmOverloads
+    constructor(
+        name: String,
+        description: String? = null
+    ) : this(name, Optional.ofNullable(description?.trim()?.ifBlank { null }))
+
+    init {
+        require(name.trim().isNotBlank()) { "Name cannot be empty." }
+        require(!name.contains(":")) { "Name cannot contain ':'." }
+        require(listOf(" ", "\n", "\t", "\r").none { name.contains(it) }) {
+            "Name cannot contain whitespace characters."
+        }
+        require(!exceeds1000CharLineLimit(this)) {
+            "The line representation of a profile MUST NOT exceed 1000 bytes."
+        }
+    }
+
+    fun hasDescription() = description.isPresent
+
+    /**
+     * Convert the profile into a String for displaying.
+     *
+     * @return string
+     */
+    override fun toString(): String =
+        if (description.isEmpty) name else "$name: ${description.get()}"
+
+    companion object {
+
+        /**
+         * Parse a [Profile] from its string representation.
+         *
+         * @param string string representation
+         * @return profile
+         */
+        @JvmStatic
+        fun parse(string: String): Profile {
+            return if (string.contains(": ")) {
+                Profile(
+                    string.substring(0, string.indexOf(": ")),
+                    string.substring(string.indexOf(": ") + 2).trim())
+            } else if (string.endsWith(":")) {
+                Profile(string.substring(0, string.length - 1))
+            } else {
+                Profile(string.trim())
+            }
+        }
+
+        /**
+         * Test if the string representation of the profile exceeds the limit of 1000 bytes length.
+         *
+         * @param profile profile
+         * @return `true` if the profile exceeds 1000 bytes, `false` otherwise.
+         */
+        @JvmStatic
+        private fun exceeds1000CharLineLimit(profile: Profile): Boolean =
+            profile.toString().toByteArray(UTF8Util.UTF8).size > 1000
+    }
+}

From 0cb5c74a11109cbe7a3b266a95f7655b8ef68441 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 12:48:23 +0100
Subject: [PATCH 06/46] Kotlin conversion: Optional

---
 sop-java/src/main/java/sop/util/Optional.java | 50 -------------------
 sop-java/src/main/kotlin/sop/util/Optional.kt | 26 ++++++++++
 2 files changed, 26 insertions(+), 50 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/util/Optional.java
 create mode 100644 sop-java/src/main/kotlin/sop/util/Optional.kt

diff --git a/sop-java/src/main/java/sop/util/Optional.java b/sop-java/src/main/java/sop/util/Optional.java
deleted file mode 100644
index 00eb201..0000000
--- a/sop-java/src/main/java/sop/util/Optional.java
+++ /dev/null
@@ -1,50 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.util;
-
-/**
- * Backport of java.util.Optional for older Android versions.
- *
- * @param <T> item type
- */
-public class Optional<T> {
-
-    private final T item;
-
-    public Optional() {
-        this(null);
-    }
-
-    public Optional(T item) {
-        this.item = item;
-    }
-
-    public static <T> Optional<T> of(T item) {
-        if (item == null) {
-            throw new NullPointerException("Item cannot be null.");
-        }
-        return new Optional<>(item);
-    }
-
-    public static <T> Optional<T> ofNullable(T item) {
-        return new Optional<>(item);
-    }
-
-    public static <T> Optional<T> ofEmpty() {
-        return new Optional<>(null);
-    }
-
-    public T get() {
-        return item;
-    }
-
-    public boolean isPresent() {
-        return item != null;
-    }
-
-    public boolean isEmpty() {
-        return item == null;
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/util/Optional.kt b/sop-java/src/main/kotlin/sop/util/Optional.kt
new file mode 100644
index 0000000..0344d0b
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/util/Optional.kt
@@ -0,0 +1,26 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.util
+
+/**
+ * Backport of java.util.Optional for older Android versions.
+ *
+ * @param <T> item type
+ */
+data class Optional<T>(val item: T? = null) {
+
+    val isPresent: Boolean = item != null
+    val isEmpty: Boolean = item == null
+
+    fun get() = item
+
+    companion object {
+        @JvmStatic fun <T> of(item: T) = Optional(item!!)
+
+        @JvmStatic fun <T> ofNullable(item: T?) = Optional(item)
+
+        @JvmStatic fun <T> ofEmpty() = Optional(null as T?)
+    }
+}

From bbe159e88c5442a61ae5dcbe7fca695f408cf785 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 12:56:12 +0100
Subject: [PATCH 07/46] Kotlin conversion: SigningResult

---
 sop-java/src/main/java/sop/SigningResult.java | 50 -------------------
 sop-java/src/main/kotlin/sop/SigningResult.kt | 28 +++++++++++
 2 files changed, 28 insertions(+), 50 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/SigningResult.java
 create mode 100644 sop-java/src/main/kotlin/sop/SigningResult.kt

diff --git a/sop-java/src/main/java/sop/SigningResult.java b/sop-java/src/main/java/sop/SigningResult.java
deleted file mode 100644
index 1ea1ba8..0000000
--- a/sop-java/src/main/java/sop/SigningResult.java
+++ /dev/null
@@ -1,50 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-/**
- * This class contains various information about a signed message.
- */
-public final class SigningResult {
-
-    private final MicAlg micAlg;
-
-    private SigningResult(MicAlg micAlg) {
-        this.micAlg = micAlg;
-    }
-
-    /**
-     * Return a string identifying the digest mechanism used to create the signed message.
-     * This is useful for setting the micalg= parameter for the multipart/signed
-     * content type of a PGP/MIME object as described in section 5 of [RFC3156].
-     * <p>
-     * If more than one signature was generated and different digest mechanisms were used,
-     * the value of the micalg object is an empty string.
-     *
-     * @return micalg
-     */
-    public MicAlg getMicAlg() {
-        return micAlg;
-    }
-
-    public static Builder builder() {
-        return new Builder();
-    }
-
-    public static class Builder {
-
-        private MicAlg micAlg;
-
-        public Builder setMicAlg(MicAlg micAlg) {
-            this.micAlg = micAlg;
-            return this;
-        }
-
-        public SigningResult build() {
-            SigningResult signingResult = new SigningResult(micAlg);
-            return signingResult;
-        }
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/SigningResult.kt b/sop-java/src/main/kotlin/sop/SigningResult.kt
new file mode 100644
index 0000000..29304ea
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/SigningResult.kt
@@ -0,0 +1,28 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+/**
+ * This class contains various information about a signed message.
+ *
+ * @param micAlg string identifying the digest mechanism used to create the signed message. This is
+ *   useful for setting the `micalg=` parameter for the multipart/signed content-type of a PGP/MIME
+ *   object as described in section 5 of [RFC3156]. If more than one signature was generated and
+ *   different digest mechanisms were used, the value of the micalg object is an empty string.
+ */
+data class SigningResult(val micAlg: MicAlg) {
+
+    class Builder internal constructor() {
+        private var micAlg = MicAlg.empty()
+
+        fun setMicAlg(micAlg: MicAlg) = apply { this.micAlg = micAlg }
+
+        fun build() = SigningResult(micAlg)
+    }
+
+    companion object {
+        @JvmStatic fun builder() = Builder()
+    }
+}

From 9dbb93e13dd14083d48622b2ff2594db41ec9de8 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:05:30 +0100
Subject: [PATCH 08/46] Kotlin conversion: MicAlg

---
 sop-java/src/main/java/sop/MicAlg.java     | 55 ----------------------
 sop-java/src/main/kotlin/sop/MicAlg.kt     | 34 +++++++++++++
 sop-java/src/test/java/sop/MicAlgTest.java |  2 +-
 3 files changed, 35 insertions(+), 56 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/MicAlg.java
 create mode 100644 sop-java/src/main/kotlin/sop/MicAlg.kt

diff --git a/sop-java/src/main/java/sop/MicAlg.java b/sop-java/src/main/java/sop/MicAlg.java
deleted file mode 100644
index 5bee787..0000000
--- a/sop-java/src/main/java/sop/MicAlg.java
+++ /dev/null
@@ -1,55 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import java.io.OutputStream;
-import java.io.PrintWriter;
-
-public class MicAlg {
-
-    private final String micAlg;
-
-    public MicAlg(String micAlg) {
-        if (micAlg == null) {
-            throw new IllegalArgumentException("MicAlg String cannot be null.");
-        }
-        this.micAlg = micAlg;
-    }
-
-    public static MicAlg empty() {
-        return new MicAlg("");
-    }
-
-    public static MicAlg fromHashAlgorithmId(int id) {
-        switch (id) {
-            case 1:
-                return new MicAlg("pgp-md5");
-            case 2:
-                return new MicAlg("pgp-sha1");
-            case 3:
-                return new MicAlg("pgp-ripemd160");
-            case 8:
-                return new MicAlg("pgp-sha256");
-            case 9:
-                return new MicAlg("pgp-sha384");
-            case 10:
-                return new MicAlg("pgp-sha512");
-            case 11:
-                return new MicAlg("pgp-sha224");
-            default:
-                throw new IllegalArgumentException("Unsupported hash algorithm ID: " + id);
-        }
-    }
-
-    public String getMicAlg() {
-        return micAlg;
-    }
-
-    public void writeTo(OutputStream outputStream) {
-        PrintWriter pw = new PrintWriter(outputStream);
-        pw.write(getMicAlg());
-        pw.close();
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/MicAlg.kt b/sop-java/src/main/kotlin/sop/MicAlg.kt
new file mode 100644
index 0000000..58ce7b5
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/MicAlg.kt
@@ -0,0 +1,34 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import java.io.OutputStream
+import java.io.PrintWriter
+
+data class MicAlg(val micAlg: String) {
+
+    fun writeTo(outputStream: OutputStream) {
+        PrintWriter(outputStream).use { it.write(micAlg) }
+    }
+
+    companion object {
+        @JvmStatic fun empty() = MicAlg("")
+
+        @JvmStatic
+        fun fromHashAlgorithmId(id: Int) =
+            when (id) {
+                1 -> "pgp-md5"
+                2 -> "pgp-sha1"
+                3 -> "pgp-ripemd160"
+                8 -> "pgp-sha256"
+                9 -> "pgp-sha384"
+                10 -> "pgp-sha512"
+                11 -> "pgp-sha224"
+                12 -> "pgp-sha3-256"
+                14 -> "pgp-sha3-512"
+                else -> throw IllegalArgumentException("Unsupported hash algorithm ID: $id")
+            }.let { MicAlg(it) }
+    }
+}
diff --git a/sop-java/src/test/java/sop/MicAlgTest.java b/sop-java/src/test/java/sop/MicAlgTest.java
index 16f54ef..7c6b30a 100644
--- a/sop-java/src/test/java/sop/MicAlgTest.java
+++ b/sop-java/src/test/java/sop/MicAlgTest.java
@@ -18,7 +18,7 @@ public class MicAlgTest {
 
     @Test
     public void constructorNullArgThrows() {
-        assertThrows(IllegalArgumentException.class, () -> new MicAlg(null));
+        assertThrows(NullPointerException.class, () -> new MicAlg(null));
     }
 
     @Test

From e6562cecff7e8c444f8d410101a6a2c70378399f Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:16:37 +0100
Subject: [PATCH 09/46] Kotlin conversion: Ready

---
 sop-java/src/main/java/sop/Ready.java | 45 ------------------------
 sop-java/src/main/kotlin/sop/Ready.kt | 49 +++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 45 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/Ready.java
 create mode 100644 sop-java/src/main/kotlin/sop/Ready.kt

diff --git a/sop-java/src/main/java/sop/Ready.java b/sop-java/src/main/java/sop/Ready.java
deleted file mode 100644
index 71ab26e..0000000
--- a/sop-java/src/main/java/sop/Ready.java
+++ /dev/null
@@ -1,45 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-
-public abstract class Ready {
-
-    /**
-     * Write the data to the provided output stream.
-     *
-     * @param outputStream output stream
-     * @throws IOException in case of an IO error
-     */
-    public abstract void writeTo(OutputStream outputStream) throws IOException;
-
-    /**
-     * Return the data as a byte array by writing it to a {@link ByteArrayOutputStream} first and then returning
-     * the array.
-     *
-     * @return data as byte array
-     * @throws IOException in case of an IO error
-     */
-    public byte[] getBytes() throws IOException {
-        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-        writeTo(bytes);
-        return bytes.toByteArray();
-    }
-
-    /**
-     * Return an input stream containing the data.
-     *
-     * @return input stream
-     * @throws IOException in case of an IO error
-     */
-    public InputStream getInputStream() throws IOException {
-        return new ByteArrayInputStream(getBytes());
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/Ready.kt b/sop-java/src/main/kotlin/sop/Ready.kt
new file mode 100644
index 0000000..1eb3fb3
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/Ready.kt
@@ -0,0 +1,49 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.io.IOException
+import java.io.InputStream
+import java.io.OutputStream
+
+/** Abstract class that encapsulates output data, waiting to be consumed. */
+abstract class Ready {
+
+    /**
+     * Write the data to the provided output stream.
+     *
+     * @param outputStream output stream
+     * @throws IOException in case of an IO error
+     */
+    @Throws(IOException::class) abstract fun writeTo(outputStream: OutputStream)
+
+    /**
+     * Return the data as a byte array by writing it to a [ByteArrayOutputStream] first and then
+     * returning the array.
+     *
+     * @return data as byte array
+     * @throws IOException in case of an IO error
+     */
+    val bytes: ByteArray
+        @Throws(IOException::class)
+        get() =
+            ByteArrayOutputStream()
+                .let {
+                    writeTo(it)
+                    it
+                }
+                .toByteArray()
+
+    /**
+     * Return an input stream containing the data.
+     *
+     * @return input stream
+     * @throws IOException in case of an IO error
+     */
+    val inputStream: InputStream
+        @Throws(IOException::class) get() = ByteArrayInputStream(bytes)
+}

From a89e70c19e63362d52b0946aeacad73e6c1bfdc9 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:23:26 +0100
Subject: [PATCH 10/46] Kotlin conversion: ReadyWithResult

---
 .../src/main/java/sop/ReadyWithResult.java    | 41 -------------------
 .../src/main/kotlin/sop/ReadyWithResult.kt    | 41 +++++++++++++++++++
 2 files changed, 41 insertions(+), 41 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/ReadyWithResult.java
 create mode 100644 sop-java/src/main/kotlin/sop/ReadyWithResult.kt

diff --git a/sop-java/src/main/java/sop/ReadyWithResult.java b/sop-java/src/main/java/sop/ReadyWithResult.java
deleted file mode 100644
index 9feedda..0000000
--- a/sop-java/src/main/java/sop/ReadyWithResult.java
+++ /dev/null
@@ -1,41 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.OutputStream;
-
-import sop.exception.SOPGPException;
-
-public abstract class ReadyWithResult<T> {
-
-    /**
-     * Write the data e.g. decrypted plaintext to the provided output stream and return the result of the
-     * processing operation.
-     *
-     * @param outputStream output stream
-     * @return result, eg. signatures
-     *
-     * @throws IOException in case of an IO error
-     * @throws SOPGPException.NoSignature if there are no valid signatures found
-     */
-    public abstract T writeTo(OutputStream outputStream) throws IOException, SOPGPException.NoSignature;
-
-    /**
-     * Return the data as a {@link ByteArrayAndResult}.
-     * Calling {@link ByteArrayAndResult#getBytes()} will give you access to the data as byte array, while
-     * {@link ByteArrayAndResult#getResult()} will grant access to the appended result.
-     *
-     * @return byte array and result
-     * @throws IOException in case of an IO error
-     * @throws SOPGPException.NoSignature if there are no valid signatures found
-     */
-    public ByteArrayAndResult<T> toByteArrayAndResult() throws IOException, SOPGPException.NoSignature {
-        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
-        T result = writeTo(bytes);
-        return new ByteArrayAndResult<>(bytes.toByteArray(), result);
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/ReadyWithResult.kt b/sop-java/src/main/kotlin/sop/ReadyWithResult.kt
new file mode 100644
index 0000000..d309c76
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/ReadyWithResult.kt
@@ -0,0 +1,41 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import java.io.ByteArrayOutputStream
+import java.io.IOException
+import java.io.OutputStream
+import sop.exception.SOPGPException
+
+abstract class ReadyWithResult<T> {
+
+    /**
+     * Write the data e.g. decrypted plaintext to the provided output stream and return the result
+     * of the processing operation.
+     *
+     * @param outputStream output stream
+     * @return result, eg. signatures
+     * @throws IOException in case of an IO error
+     * @throws SOPGPException in case of a SOP protocol error
+     */
+    @Throws(IOException::class, SOPGPException::class)
+    abstract fun writeTo(outputStream: OutputStream): T
+
+    /**
+     * Return the data as a [ByteArrayAndResult]. Calling [ByteArrayAndResult.bytes] will give you
+     * access to the data as byte array, while [ByteArrayAndResult.result] will grant access to the
+     * appended result.
+     *
+     * @return byte array and result
+     * @throws IOException in case of an IO error
+     * @throws SOPGPException.NoSignature if there are no valid signatures found
+     */
+    @Throws(IOException::class, SOPGPException::class)
+    fun toByteArrayAndResult() =
+        ByteArrayOutputStream().let {
+            val result = writeTo(it)
+            ByteArrayAndResult(it.toByteArray(), result)
+        }
+}

From 2391ffc9b2c5e6585f8eb24219e741eb7cfdd031 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:26:33 +0100
Subject: [PATCH 11/46] Kotlin conversion: DecryptionResult

---
 .../src/main/java/sop/DecryptionResult.java   | 29 -------------------
 .../src/main/kotlin/sop/DecryptionResult.kt   | 16 ++++++++++
 2 files changed, 16 insertions(+), 29 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/DecryptionResult.java
 create mode 100644 sop-java/src/main/kotlin/sop/DecryptionResult.kt

diff --git a/sop-java/src/main/java/sop/DecryptionResult.java b/sop-java/src/main/java/sop/DecryptionResult.java
deleted file mode 100644
index 4f0e1ab..0000000
--- a/sop-java/src/main/java/sop/DecryptionResult.java
+++ /dev/null
@@ -1,29 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import sop.util.Optional;
-
-public class DecryptionResult {
-
-    private final Optional<SessionKey> sessionKey;
-    private final List<Verification> verifications;
-
-    public DecryptionResult(SessionKey sessionKey, List<Verification> verifications) {
-        this.sessionKey = Optional.ofNullable(sessionKey);
-        this.verifications = Collections.unmodifiableList(verifications);
-    }
-
-    public Optional<SessionKey> getSessionKey() {
-        return sessionKey;
-    }
-
-    public List<Verification> getVerifications() {
-        return new ArrayList<>(verifications);
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/DecryptionResult.kt b/sop-java/src/main/kotlin/sop/DecryptionResult.kt
new file mode 100644
index 0000000..1ba98bb
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/DecryptionResult.kt
@@ -0,0 +1,16 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import sop.util.Optional
+
+data class DecryptionResult
+internal constructor(val sessionKey: Optional<SessionKey>, val verifications: List<Verification>) {
+
+    constructor(
+        sessionKey: SessionKey?,
+        verifications: List<Verification>
+    ) : this(Optional.ofNullable(sessionKey), verifications)
+}

From dc23c8aa98a9f141af6051da1415b82dfe3a9f70 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:29:58 +0100
Subject: [PATCH 12/46] Kotlin conversion: Signatures

---
 sop-java/src/main/java/sop/Signatures.java | 21 ---------------------
 sop-java/src/main/kotlin/sop/Signatures.kt | 19 +++++++++++++++++++
 2 files changed, 19 insertions(+), 21 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/Signatures.java
 create mode 100644 sop-java/src/main/kotlin/sop/Signatures.kt

diff --git a/sop-java/src/main/java/sop/Signatures.java b/sop-java/src/main/java/sop/Signatures.java
deleted file mode 100644
index dd3f000..0000000
--- a/sop-java/src/main/java/sop/Signatures.java
+++ /dev/null
@@ -1,21 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import java.io.IOException;
-import java.io.OutputStream;
-
-public abstract class Signatures extends Ready {
-
-    /**
-     * Write OpenPGP signatures to the provided output stream.
-     *
-     * @param signatureOutputStream output stream
-     * @throws IOException in case of an IO error
-     */
-    @Override
-    public abstract void writeTo(OutputStream signatureOutputStream) throws IOException;
-
-}
diff --git a/sop-java/src/main/kotlin/sop/Signatures.kt b/sop-java/src/main/kotlin/sop/Signatures.kt
new file mode 100644
index 0000000..63aafe9
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/Signatures.kt
@@ -0,0 +1,19 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import java.io.IOException
+import java.io.OutputStream
+
+abstract class Signatures : Ready() {
+
+    /**
+     * Write OpenPGP signatures to the provided output stream.
+     *
+     * @param outputStream signature output stream
+     * @throws IOException in case of an IO error
+     */
+    @Throws(IOException::class) abstract override fun writeTo(outputStream: OutputStream)
+}

From 31409b7949415b995c5a3a7cf52ad4af40b640bd Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:38:53 +0100
Subject: [PATCH 13/46] Kotlin conversion: SOP

---
 sop-java/src/main/java/sop/SOP.java | 177 ----------------------------
 sop-java/src/main/kotlin/sop/SOP.kt |  97 +++++++++++++++
 2 files changed, 97 insertions(+), 177 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/SOP.java
 create mode 100644 sop-java/src/main/kotlin/sop/SOP.kt

diff --git a/sop-java/src/main/java/sop/SOP.java b/sop-java/src/main/java/sop/SOP.java
deleted file mode 100644
index 1200e21..0000000
--- a/sop-java/src/main/java/sop/SOP.java
+++ /dev/null
@@ -1,177 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop;
-
-import sop.operation.Armor;
-import sop.operation.ChangeKeyPassword;
-import sop.operation.Dearmor;
-import sop.operation.Decrypt;
-import sop.operation.Encrypt;
-import sop.operation.ExtractCert;
-import sop.operation.GenerateKey;
-import sop.operation.InlineDetach;
-import sop.operation.InlineSign;
-import sop.operation.InlineVerify;
-import sop.operation.DetachedSign;
-import sop.operation.DetachedVerify;
-import sop.operation.ListProfiles;
-import sop.operation.RevokeKey;
-import sop.operation.Version;
-
-/**
- * Stateless OpenPGP Interface.
- * This class provides a stateless interface to various OpenPGP related operations.
- * <br>
- * Note: Subcommand objects acquired by calling any method of this interface are not intended for reuse.
- * If you for example need to generate multiple keys, make a dedicated call to {@link #generateKey()} once per
- * key generation.
- */
-public interface SOP {
-
-    /**
-     * Get information about the implementations name and version.
-     *
-     * @return version
-     */
-    Version version();
-
-    /**
-     * Generate a secret key.
-     * Customize the operation using the builder {@link GenerateKey}.
-     *
-     * @return builder instance
-     */
-    GenerateKey generateKey();
-
-    /**
-     * Extract a certificate (public key) from a secret key.
-     * Customize the operation using the builder {@link ExtractCert}.
-     *
-     * @return builder instance
-     */
-    ExtractCert extractCert();
-
-    /**
-     * Create detached signatures.
-     * Customize the operation using the builder {@link DetachedSign}.
-     * <p>
-     * If you want to sign a message inline, use {@link #inlineSign()} instead.
-     *
-     * @return builder instance
-     */
-    default DetachedSign sign() {
-        return detachedSign();
-    }
-
-    /**
-     * Create detached signatures.
-     * Customize the operation using the builder {@link DetachedSign}.
-     * <p>
-     * If you want to sign a message inline, use {@link #inlineSign()} instead.
-     *
-     * @return builder instance
-     */
-    DetachedSign detachedSign();
-
-    /**
-     * Sign a message using inline signatures.
-     * <p>
-     * If you need to create detached signatures, use {@link #detachedSign()} instead.
-     *
-     * @return builder instance
-     */
-    InlineSign inlineSign();
-
-    /**
-     * Verify detached signatures.
-     * Customize the operation using the builder {@link DetachedVerify}.
-     * <p>
-     * If you need to verify an inline-signed message, use {@link #inlineVerify()} instead.
-     *
-     * @return builder instance
-     */
-    default DetachedVerify verify() {
-        return detachedVerify();
-    }
-
-    /**
-     * Verify detached signatures.
-     * Customize the operation using the builder {@link DetachedVerify}.
-     * <p>
-     * If you need to verify an inline-signed message, use {@link #inlineVerify()} instead.
-     *
-     * @return builder instance
-     */
-    DetachedVerify detachedVerify();
-
-    /**
-     * Verify signatures of an inline-signed message.
-     * <p>
-     * If you need to verify detached signatures over a message, use {@link #detachedVerify()} instead.
-     *
-     * @return builder instance
-     */
-    InlineVerify inlineVerify();
-
-    /**
-     * Detach signatures from an inline signed message.
-     *
-     * @return builder instance
-     */
-    InlineDetach inlineDetach();
-
-    /**
-     * Encrypt a message.
-     * Customize the operation using the builder {@link Encrypt}.
-     *
-     * @return builder instance
-     */
-    Encrypt encrypt();
-
-    /**
-     * Decrypt a message.
-     * Customize the operation using the builder {@link Decrypt}.
-     *
-     * @return builder instance
-     */
-    Decrypt decrypt();
-
-    /**
-     * Convert binary OpenPGP data to ASCII.
-     * Customize the operation using the builder {@link Armor}.
-     *
-     * @return builder instance
-     */
-    Armor armor();
-
-    /**
-     * Converts ASCII armored OpenPGP data to binary.
-     * Customize the operation using the builder {@link Dearmor}.
-     *
-     * @return builder instance
-     */
-    Dearmor dearmor();
-
-    /**
-     * List supported {@link Profile Profiles} of a subcommand.
-     *
-     * @return builder instance
-     */
-    ListProfiles listProfiles();
-
-    /**
-     * Revoke one or more secret keys.
-     *
-     * @return builder instance
-     */
-    RevokeKey revokeKey();
-
-    /**
-     * Update a key's password.
-     *
-     * @return builder instance
-     */
-    ChangeKeyPassword changeKeyPassword();
-}
diff --git a/sop-java/src/main/kotlin/sop/SOP.kt b/sop-java/src/main/kotlin/sop/SOP.kt
new file mode 100644
index 0000000..e01763a
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/SOP.kt
@@ -0,0 +1,97 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop
+
+import sop.operation.Armor
+import sop.operation.ChangeKeyPassword
+import sop.operation.Dearmor
+import sop.operation.Decrypt
+import sop.operation.DetachedSign
+import sop.operation.DetachedVerify
+import sop.operation.Encrypt
+import sop.operation.ExtractCert
+import sop.operation.GenerateKey
+import sop.operation.InlineDetach
+import sop.operation.InlineSign
+import sop.operation.InlineVerify
+import sop.operation.ListProfiles
+import sop.operation.RevokeKey
+import sop.operation.Version
+
+/**
+ * Stateless OpenPGP Interface. This class provides a stateless interface to various OpenPGP related
+ * operations. Note: Subcommand objects acquired by calling any method of this interface are not
+ * intended for reuse. If you for example need to generate multiple keys, make a dedicated call to
+ * [generateKey] once per key generation.
+ */
+interface SOP {
+
+    /** Get information about the implementations name and version. */
+    fun version(): Version
+
+    /** Generate a secret key. */
+    fun generateKey(): GenerateKey
+
+    /** Extract a certificate (public key) from a secret key. */
+    fun extractCert(): ExtractCert
+
+    /**
+     * Create detached signatures. If you want to sign a message inline, use [inlineSign] instead.
+     */
+    fun sign(): DetachedSign = detachedSign()
+
+    /**
+     * Create detached signatures. If you want to sign a message inline, use [inlineSign] instead.
+     */
+    fun detachedSign(): DetachedSign
+
+    /**
+     * Sign a message using inline signatures. If you need to create detached signatures, use
+     * [detachedSign] instead.
+     */
+    fun inlineSign(): InlineSign
+
+    /**
+     * Verify detached signatures. If you need to verify an inline-signed message, use
+     * [inlineVerify] instead.
+     */
+    fun verify(): DetachedVerify = detachedVerify()
+
+    /**
+     * Verify detached signatures. If you need to verify an inline-signed message, use
+     * [inlineVerify] instead.
+     */
+    fun detachedVerify(): DetachedVerify
+
+    /**
+     * Verify signatures of an inline-signed message. If you need to verify detached signatures over
+     * a message, use [detachedVerify] instead.
+     */
+    fun inlineVerify(): InlineVerify
+
+    /** Detach signatures from an inline signed message. */
+    fun inlineDetach(): InlineDetach
+
+    /** Encrypt a message. */
+    fun encrypt(): Encrypt
+
+    /** Decrypt a message. */
+    fun decrypt(): Decrypt
+
+    /** Convert binary OpenPGP data to ASCII. */
+    fun armor(): Armor
+
+    /** Converts ASCII armored OpenPGP data to binary. */
+    fun dearmor(): Dearmor
+
+    /** List supported [Profiles][Profile] of a subcommand. */
+    fun listProfiles(): ListProfiles
+
+    /** Revoke one or more secret keys. */
+    fun revokeKey(): RevokeKey
+
+    /** Update a key's password. */
+    fun changeKeyPassword(): ChangeKeyPassword
+}

From e68d6df57f86da9b4881205fe7f6b455d25c8690 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:50:46 +0100
Subject: [PATCH 14/46] Kotlin conversion: AbstractSign

---
 .../main/java/sop/operation/AbstractSign.java | 85 -------------------
 .../main/kotlin/sop/operation/AbstractSign.kt | 79 +++++++++++++++++
 2 files changed, 79 insertions(+), 85 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/AbstractSign.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/AbstractSign.kt

diff --git a/sop-java/src/main/java/sop/operation/AbstractSign.java b/sop-java/src/main/java/sop/operation/AbstractSign.java
deleted file mode 100644
index 508d741..0000000
--- a/sop-java/src/main/java/sop/operation/AbstractSign.java
+++ /dev/null
@@ -1,85 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.exception.SOPGPException;
-import sop.util.UTF8Util;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-public interface AbstractSign<T> {
-
-    /**
-     * Disable ASCII armor encoding.
-     *
-     * @return builder instance
-     */
-    T noArmor();
-
-    /**
-     * Add one or more signing keys.
-     *
-     * @param key input stream containing encoded keys
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.KeyCannotSign if the key cannot be used for signing
-     * @throws sop.exception.SOPGPException.BadData if the {@link InputStream} does not contain an OpenPGP key
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
-     * @throws IOException in case of an IO error
-     */
-    T key(InputStream key)
-            throws SOPGPException.KeyCannotSign,
-            SOPGPException.BadData,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            IOException;
-
-    /**
-     * Add one or more signing keys.
-     *
-     * @param key byte array containing encoded keys
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.KeyCannotSign if the key cannot be used for signing
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an OpenPGP key
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
-     * @throws IOException in case of an IO error
-     */
-    default T key(byte[] key)
-            throws SOPGPException.KeyCannotSign,
-            SOPGPException.BadData,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            IOException {
-        return key(new ByteArrayInputStream(key));
-    }
-
-    /**
-     * Provide the password for the secret key used for signing.
-     *
-     * @param password password
-     * @return builder instance
-     * @throws sop.exception.SOPGPException.UnsupportedOption if key passwords are not supported
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the provided passphrase is not human-readable
-     */
-    default T withKeyPassword(String password)
-            throws SOPGPException.UnsupportedOption,
-            SOPGPException.PasswordNotHumanReadable {
-        return withKeyPassword(password.getBytes(UTF8Util.UTF8));
-    }
-
-    /**
-     * Provide the password for the secret key used for signing.
-     *
-     * @param password password
-     * @return builder instance
-     * @throws sop.exception.SOPGPException.UnsupportedOption if key passwords are not supported
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the provided passphrase is not human-readable
-     */
-    T withKeyPassword(byte[] password)
-            throws SOPGPException.UnsupportedOption,
-            SOPGPException.PasswordNotHumanReadable;
-
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/AbstractSign.kt b/sop-java/src/main/kotlin/sop/operation/AbstractSign.kt
new file mode 100644
index 0000000..0258432
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/AbstractSign.kt
@@ -0,0 +1,79 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import sop.exception.SOPGPException.BadData
+import sop.exception.SOPGPException.KeyCannotSign
+import sop.exception.SOPGPException.PasswordNotHumanReadable
+import sop.exception.SOPGPException.UnsupportedAsymmetricAlgo
+import sop.exception.SOPGPException.UnsupportedOption
+import sop.util.UTF8Util
+
+/**
+ * Interface for signing operations.
+ *
+ * @param <T> builder subclass
+ */
+interface AbstractSign<T> {
+
+    /**
+     * Disable ASCII armor encoding.
+     *
+     * @return builder instance
+     */
+    fun noArmor(): T
+
+    /**
+     * Add one or more signing keys.
+     *
+     * @param key input stream containing encoded keys
+     * @return builder instance
+     * @throws KeyCannotSign if the key cannot be used for signing
+     * @throws BadData if the [InputStream] does not contain an OpenPGP key
+     * @throws UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
+     * @throws IOException in case of an IO error
+     */
+    @Throws(
+        KeyCannotSign::class, BadData::class, UnsupportedAsymmetricAlgo::class, IOException::class)
+    fun key(key: InputStream): T
+
+    /**
+     * Add one or more signing keys.
+     *
+     * @param key byte array containing encoded keys
+     * @return builder instance
+     * @throws KeyCannotSign if the key cannot be used for signing
+     * @throws BadData if the byte array does not contain an OpenPGP key
+     * @throws UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
+     * @throws IOException in case of an IO error
+     */
+    @Throws(
+        KeyCannotSign::class, BadData::class, UnsupportedAsymmetricAlgo::class, IOException::class)
+    fun key(key: ByteArray): T = key(key.inputStream())
+
+    /**
+     * Provide the password for the secret key used for signing.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws UnsupportedOption if key passwords are not supported
+     * @throws PasswordNotHumanReadable if the provided passphrase is not human-readable
+     */
+    @Throws(UnsupportedOption::class, PasswordNotHumanReadable::class)
+    fun withKeyPassword(password: String): T = withKeyPassword(password.toByteArray(UTF8Util.UTF8))
+
+    /**
+     * Provide the password for the secret key used for signing.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws UnsupportedOption if key passwords are not supported
+     * @throws PasswordNotHumanReadable if the provided passphrase is not human-readable
+     */
+    @Throws(UnsupportedOption::class, PasswordNotHumanReadable::class)
+    fun withKeyPassword(password: ByteArray): T
+}

From 08ddc5d8a529aa1acfb65b7e849a82b2ca596534 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:51:30 +0100
Subject: [PATCH 15/46] Kotlin conversion: AbstractVerify

---
 .../java/sop/operation/AbstractVerify.java    | 68 -------------------
 .../kotlin/sop/operation/AbstractVerify.kt    | 57 ++++++++++++++++
 2 files changed, 57 insertions(+), 68 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/AbstractVerify.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/AbstractVerify.kt

diff --git a/sop-java/src/main/java/sop/operation/AbstractVerify.java b/sop-java/src/main/java/sop/operation/AbstractVerify.java
deleted file mode 100644
index 51d84b7..0000000
--- a/sop-java/src/main/java/sop/operation/AbstractVerify.java
+++ /dev/null
@@ -1,68 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.exception.SOPGPException;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.Date;
-
-/**
- * Common API methods shared between verification of inline signatures ({@link InlineVerify})
- * and verification of detached signatures ({@link DetachedVerify}).
- *
- * @param <T> Builder type ({@link DetachedVerify}, {@link InlineVerify})
- */
-public interface AbstractVerify<T> {
-
-    /**
-     * Makes the SOP implementation consider signatures before this date invalid.
-     *
-     * @param timestamp timestamp
-     * @return builder instance
-     */
-    T notBefore(Date timestamp)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Makes the SOP implementation consider signatures after this date invalid.
-     *
-     * @param timestamp timestamp
-     * @return builder instance
-     */
-    T notAfter(Date timestamp)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Add one or more verification cert.
-     *
-     * @param cert input stream containing the encoded certs
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.BadData if the input stream does not contain an OpenPGP certificate
-     * @throws IOException in case of an IO error
-     */
-    T cert(InputStream cert)
-            throws SOPGPException.BadData,
-            IOException;
-
-    /**
-     * Add one or more verification cert.
-     *
-     * @param cert byte array containing the encoded certs
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an OpenPGP certificate
-     * @throws IOException in case of an IO error
-     */
-    default T cert(byte[] cert)
-            throws SOPGPException.BadData,
-            IOException {
-        return cert(new ByteArrayInputStream(cert));
-    }
-
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/AbstractVerify.kt b/sop-java/src/main/kotlin/sop/operation/AbstractVerify.kt
new file mode 100644
index 0000000..3554ea3
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/AbstractVerify.kt
@@ -0,0 +1,57 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import java.util.*
+import sop.exception.SOPGPException.BadData
+import sop.exception.SOPGPException.UnsupportedOption
+
+/**
+ * Common API methods shared between verification of inline signatures ([InlineVerify]) and
+ * verification of detached signatures ([DetachedVerify]).
+ *
+ * @param <T> Builder type ([DetachedVerify], [InlineVerify])
+ */
+interface AbstractVerify<T> {
+
+    /**
+     * Makes the SOP implementation consider signatures before this date invalid.
+     *
+     * @param timestamp timestamp
+     * @return builder instance
+     */
+    @Throws(UnsupportedOption::class) fun notBefore(timestamp: Date): T
+
+    /**
+     * Makes the SOP implementation consider signatures after this date invalid.
+     *
+     * @param timestamp timestamp
+     * @return builder instance
+     */
+    @Throws(UnsupportedOption::class) fun notAfter(timestamp: Date): T
+
+    /**
+     * Add one or more verification cert.
+     *
+     * @param cert input stream containing the encoded certs
+     * @return builder instance
+     * @throws BadData if the input stream does not contain an OpenPGP certificate
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class) fun cert(cert: InputStream): T
+
+    /**
+     * Add one or more verification cert.
+     *
+     * @param cert byte array containing the encoded certs
+     * @return builder instance
+     * @throws BadData if the byte array does not contain an OpenPGP certificate
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class)
+    fun cert(cert: ByteArray): T = cert(cert.inputStream())
+}

From 4a123a198078f81c80640716d51c574a956dccda Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 13:54:24 +0100
Subject: [PATCH 16/46] Kotlin conversion: Armor

---
 .../src/main/java/sop/operation/Armor.java    | 53 -------------------
 .../src/main/kotlin/sop/operation/Armor.kt    | 46 ++++++++++++++++
 2 files changed, 46 insertions(+), 53 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/Armor.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/Armor.kt

diff --git a/sop-java/src/main/java/sop/operation/Armor.java b/sop-java/src/main/java/sop/operation/Armor.java
deleted file mode 100644
index a625808..0000000
--- a/sop-java/src/main/java/sop/operation/Armor.java
+++ /dev/null
@@ -1,53 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-import sop.Ready;
-import sop.enums.ArmorLabel;
-import sop.exception.SOPGPException;
-
-public interface Armor {
-
-    /**
-     * Overrides automatic detection of label.
-     *
-     * @param label armor label
-     * @return builder instance
-     */
-    Armor label(ArmorLabel label)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Armor the provided data.
-     *
-     * @param data input stream of unarmored OpenPGP data
-     * @return armored data
-     *
-     * @throws sop.exception.SOPGPException.BadData if the data appears to be OpenPGP packets, but those are broken
-     * @throws IOException in case of an IO error
-     */
-    Ready data(InputStream data)
-            throws SOPGPException.BadData,
-            IOException;
-
-    /**
-     * Armor the provided data.
-     *
-     * @param data unarmored OpenPGP data
-     * @return armored data
-     *
-     * @throws sop.exception.SOPGPException.BadData if the data appears to be OpenPGP packets, but those are broken
-     * @throws IOException in case of an IO error
-     */
-    default Ready data(byte[] data)
-            throws SOPGPException.BadData,
-            IOException {
-        return data(new ByteArrayInputStream(data));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/Armor.kt b/sop-java/src/main/kotlin/sop/operation/Armor.kt
new file mode 100644
index 0000000..e89708b
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/Armor.kt
@@ -0,0 +1,46 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import sop.Ready
+import sop.enums.ArmorLabel
+import sop.exception.SOPGPException.BadData
+import sop.exception.SOPGPException.UnsupportedOption
+
+interface Armor {
+
+    /**
+     * Overrides automatic detection of label.
+     *
+     * @param label armor label
+     * @return builder instance
+     */
+    @Deprecated("Use of armor labels is deprecated and will be removed in a future release.")
+    @Throws(UnsupportedOption::class)
+    fun label(label: ArmorLabel): Armor
+
+    /**
+     * Armor the provided data.
+     *
+     * @param data input stream of unarmored OpenPGP data
+     * @return armored data
+     * @throws BadData if the data appears to be OpenPGP packets, but those are broken
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class) fun data(data: InputStream): Ready
+
+    /**
+     * Armor the provided data.
+     *
+     * @param data unarmored OpenPGP data
+     * @return armored data
+     * @throws BadData if the data appears to be OpenPGP packets, but those are broken
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class)
+    fun data(data: ByteArray): Ready = data(data.inputStream())
+}

From 34e1d8992f2b6adb626dd25dd6c940a233a687bc Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:00:49 +0100
Subject: [PATCH 17/46] Kotlin conversion: ChangeKeyPassword

---
 .../java/sop/operation/ChangeKeyPassword.java | 83 ----------------
 .../kotlin/sop/operation/ChangeKeyPassword.kt | 95 +++++++++++++++++++
 2 files changed, 95 insertions(+), 83 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/ChangeKeyPassword.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/ChangeKeyPassword.kt

diff --git a/sop-java/src/main/java/sop/operation/ChangeKeyPassword.java b/sop-java/src/main/java/sop/operation/ChangeKeyPassword.java
deleted file mode 100644
index 460a20a..0000000
--- a/sop-java/src/main/java/sop/operation/ChangeKeyPassword.java
+++ /dev/null
@@ -1,83 +0,0 @@
-// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.Ready;
-import sop.exception.SOPGPException;
-import sop.util.UTF8Util;
-
-import java.io.ByteArrayInputStream;
-import java.io.InputStream;
-import java.nio.charset.CharacterCodingException;
-
-public interface ChangeKeyPassword {
-
-    /**
-     * Disable ASCII armoring of the output.
-     *
-     * @return builder instance
-     */
-    ChangeKeyPassword noArmor();
-
-    default ChangeKeyPassword oldKeyPassphrase(byte[] password) {
-        try {
-            return oldKeyPassphrase(UTF8Util.decodeUTF8(password));
-        } catch (CharacterCodingException e) {
-            throw new SOPGPException.PasswordNotHumanReadable("Password MUST be a valid UTF8 string.");
-        }
-    }
-
-    /**
-     * Provide a passphrase to unlock the secret key.
-     * This method can be provided multiple times to provide separate passphrases that are tried as a
-     * means to unlock any secret key material encountered.
-     *
-     * @param oldPassphrase old passphrase
-     * @return builder instance
-     */
-    ChangeKeyPassword oldKeyPassphrase(String oldPassphrase);
-
-    /**
-     * Provide a passphrase to re-lock the secret key with.
-     * This method can only be used once, and all key material encountered will be encrypted with the given passphrase.
-     * If this method is not called, the key material will not be protected.
-     *
-     * @param newPassphrase new passphrase
-     * @return builder instance
-     */
-    default ChangeKeyPassword newKeyPassphrase(byte[] newPassphrase) {
-        try {
-            return newKeyPassphrase(UTF8Util.decodeUTF8(newPassphrase));
-        } catch (CharacterCodingException e) {
-            throw new SOPGPException.PasswordNotHumanReadable("Password MUST be a valid UTF8 string.");
-        }
-    }
-
-    /**
-     * Provide a passphrase to re-lock the secret key with.
-     * This method can only be used once, and all key material encountered will be encrypted with the given passphrase.
-     * If this method is not called, the key material will not be protected.
-     *
-     * @param newPassphrase new passphrase
-     * @return builder instance
-     */
-    ChangeKeyPassword newKeyPassphrase(String newPassphrase);
-
-    default Ready keys(byte[] keys) throws SOPGPException.KeyIsProtected, SOPGPException.BadData {
-        return keys(new ByteArrayInputStream(keys));
-    }
-
-    /**
-     * Provide the key material.
-     *
-     * @param inputStream input stream of secret key material
-     * @return ready
-     *
-     * @throws sop.exception.SOPGPException.KeyIsProtected if any (sub-) key encountered cannot be unlocked.
-     * @throws sop.exception.SOPGPException.BadData if the key material is malformed
-     */
-    Ready keys(InputStream inputStream) throws SOPGPException.KeyIsProtected, SOPGPException.BadData;
-
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/ChangeKeyPassword.kt b/sop-java/src/main/kotlin/sop/operation/ChangeKeyPassword.kt
new file mode 100644
index 0000000..224e0f4
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/ChangeKeyPassword.kt
@@ -0,0 +1,95 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.InputStream
+import sop.Ready
+import sop.exception.SOPGPException.BadData
+import sop.exception.SOPGPException.KeyIsProtected
+import sop.exception.SOPGPException.PasswordNotHumanReadable
+import sop.util.UTF8Util
+
+interface ChangeKeyPassword {
+
+    /**
+     * Disable ASCII armoring of the output.
+     *
+     * @return builder instance
+     */
+    fun noArmor(): ChangeKeyPassword
+
+    /**
+     * Provide a passphrase to unlock the secret key. This method can be provided multiple times to
+     * provide separate passphrases that are tried as a means to unlock any secret key material
+     * encountered.
+     *
+     * @param oldPassphrase old passphrase
+     * @return builder instance
+     */
+    @Throws(PasswordNotHumanReadable::class)
+    fun oldKeyPassphrase(oldPassphrase: ByteArray): ChangeKeyPassword =
+        try {
+            oldKeyPassphrase(UTF8Util.decodeUTF8(oldPassphrase))
+        } catch (e: CharacterCodingException) {
+            throw PasswordNotHumanReadable("Password MUST be a valid UTF8 string.")
+        }
+
+    /**
+     * Provide a passphrase to unlock the secret key. This method can be provided multiple times to
+     * provide separate passphrases that are tried as a means to unlock any secret key material
+     * encountered.
+     *
+     * @param oldPassphrase old passphrase
+     * @return builder instance
+     */
+    fun oldKeyPassphrase(oldPassphrase: String): ChangeKeyPassword
+
+    /**
+     * Provide a passphrase to re-lock the secret key with. This method can only be used once, and
+     * all key material encountered will be encrypted with the given passphrase. If this method is
+     * not called, the key material will not be protected.
+     *
+     * @param newPassphrase new passphrase
+     * @return builder instance
+     */
+    @Throws(PasswordNotHumanReadable::class)
+    fun newKeyPassphrase(newPassphrase: ByteArray): ChangeKeyPassword =
+        try {
+            newKeyPassphrase(UTF8Util.decodeUTF8(newPassphrase))
+        } catch (e: CharacterCodingException) {
+            throw PasswordNotHumanReadable("Password MUST be a valid UTF8 string.")
+        }
+
+    /**
+     * Provide a passphrase to re-lock the secret key with. This method can only be used once, and
+     * all key material encountered will be encrypted with the given passphrase. If this method is
+     * not called, the key material will not be protected.
+     *
+     * @param newPassphrase new passphrase
+     * @return builder instance
+     */
+    fun newKeyPassphrase(newPassphrase: String): ChangeKeyPassword
+
+    /**
+     * Provide the key material.
+     *
+     * @param keys input stream of secret key material
+     * @return ready
+     * @throws KeyIsProtected if any (sub-) key encountered cannot be unlocked.
+     * @throws BadData if the key material is malformed
+     */
+    @Throws(KeyIsProtected::class, BadData::class)
+    fun keys(keys: ByteArray): Ready = keys(keys.inputStream())
+
+    /**
+     * Provide the key material.
+     *
+     * @param keys input stream of secret key material
+     * @return ready
+     * @throws KeyIsProtected if any (sub-) key encountered cannot be unlocked.
+     * @throws BadData if the key material is malformed
+     */
+    @Throws(KeyIsProtected::class, BadData::class) fun keys(keys: InputStream): Ready
+}

From 39c222dfc893d780d8daaee8fd47854ecb17d143 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:03:18 +0100
Subject: [PATCH 18/46] Kotlin conversion: Dearmor

---
 .../src/main/java/sop/operation/Dearmor.java  | 59 -------------------
 .../src/main/kotlin/sop/operation/Dearmor.kt  | 46 +++++++++++++++
 2 files changed, 46 insertions(+), 59 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/Dearmor.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/Dearmor.kt

diff --git a/sop-java/src/main/java/sop/operation/Dearmor.java b/sop-java/src/main/java/sop/operation/Dearmor.java
deleted file mode 100644
index 524dc8c..0000000
--- a/sop-java/src/main/java/sop/operation/Dearmor.java
+++ /dev/null
@@ -1,59 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-import sop.Ready;
-import sop.exception.SOPGPException;
-import sop.util.UTF8Util;
-
-public interface Dearmor {
-
-    /**
-     * Dearmor armored OpenPGP data.
-     *
-     * @param data armored OpenPGP data
-     * @return input stream of unarmored data
-     *
-     * @throws SOPGPException.BadData in case of non-OpenPGP data
-     * @throws IOException in case of an IO error
-     */
-    Ready data(InputStream data)
-            throws SOPGPException.BadData,
-            IOException;
-
-    /**
-     * Dearmor armored OpenPGP data.
-     *
-     * @param data armored OpenPGP data
-     * @return input stream of unarmored data
-     *
-     * @throws SOPGPException.BadData in case of non-OpenPGP data
-     * @throws IOException in case of an IO error
-     */
-    default Ready data(byte[] data)
-            throws SOPGPException.BadData,
-            IOException {
-        return data(new ByteArrayInputStream(data));
-    }
-
-    /**
-     * Dearmor amored OpenPGP data.
-     *
-     * @param data armored OpenPGP data
-     * @return input stream of unarmored data
-     *
-     * @throws SOPGPException.BadData in case of non-OpenPGP data
-     * @throws IOException in case of an IO error
-     */
-    default Ready data(String data)
-            throws SOPGPException.BadData,
-            IOException {
-        return data(data.getBytes(UTF8Util.UTF8));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/Dearmor.kt b/sop-java/src/main/kotlin/sop/operation/Dearmor.kt
new file mode 100644
index 0000000..cc5e98d
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/Dearmor.kt
@@ -0,0 +1,46 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import sop.Ready
+import sop.exception.SOPGPException.BadData
+import sop.util.UTF8Util
+
+interface Dearmor {
+
+    /**
+     * Dearmor armored OpenPGP data.
+     *
+     * @param data armored OpenPGP data
+     * @return input stream of unarmored data
+     * @throws BadData in case of non-OpenPGP data
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class) fun data(data: InputStream): Ready
+
+    /**
+     * Dearmor armored OpenPGP data.
+     *
+     * @param data armored OpenPGP data
+     * @return input stream of unarmored data
+     * @throws BadData in case of non-OpenPGP data
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class)
+    fun data(data: ByteArray): Ready = data(data.inputStream())
+
+    /**
+     * Dearmor amored OpenPGP data.
+     *
+     * @param data armored OpenPGP data
+     * @return input stream of unarmored data
+     * @throws BadData in case of non-OpenPGP data
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class)
+    fun data(data: String): Ready = data(data.toByteArray(UTF8Util.UTF8))
+}

From 91a861b5c366d54ddff4b1625e920e0e75d476cb Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:08:03 +0100
Subject: [PATCH 19/46] Kotlin conversion: Decrypt

---
 .../src/main/java/sop/operation/Decrypt.java  | 193 ------------------
 .../src/main/kotlin/sop/operation/Decrypt.kt  | 169 +++++++++++++++
 2 files changed, 169 insertions(+), 193 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/Decrypt.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/Decrypt.kt

diff --git a/sop-java/src/main/java/sop/operation/Decrypt.java b/sop-java/src/main/java/sop/operation/Decrypt.java
deleted file mode 100644
index 0123bbc..0000000
--- a/sop-java/src/main/java/sop/operation/Decrypt.java
+++ /dev/null
@@ -1,193 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.DecryptionResult;
-import sop.ReadyWithResult;
-import sop.SessionKey;
-import sop.exception.SOPGPException;
-import sop.util.UTF8Util;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.Date;
-
-public interface Decrypt {
-
-    /**
-     * Makes the SOP consider signatures before this date invalid.
-     *
-     * @param timestamp timestamp
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.UnsupportedOption if this option is not supported
-     */
-    Decrypt verifyNotBefore(Date timestamp)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Makes the SOP consider signatures after this date invalid.
-     *
-     * @param timestamp timestamp
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.UnsupportedOption if this option is not supported
-     */
-    Decrypt verifyNotAfter(Date timestamp)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Adds one or more verification cert.
-     *
-     * @param cert input stream containing the cert(s)
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.BadData if the {@link InputStream} doesn't provide an OpenPGP certificate
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the cert uses an unsupported asymmetric algorithm
-     * @throws IOException in case of an IO error
-     */
-    Decrypt verifyWithCert(InputStream cert)
-            throws SOPGPException.BadData,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            IOException;
-
-    /**
-     * Adds one or more verification cert.
-     *
-     * @param cert byte array containing the cert(s)
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.BadData if the byte array doesn't contain an OpenPGP certificate
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the cert uses an unsupported asymmetric algorithm
-     * @throws IOException in case of an IO error
-     */
-    default Decrypt verifyWithCert(byte[] cert)
-            throws SOPGPException.BadData,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            IOException {
-        return verifyWithCert(new ByteArrayInputStream(cert));
-    }
-
-    /**
-     * Tries to decrypt with the given session key.
-     *
-     * @param sessionKey session key
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.UnsupportedOption if this option is not supported
-     */
-    Decrypt withSessionKey(SessionKey sessionKey)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Tries to decrypt with the given password.
-     *
-     * @param password password
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     * @throws sop.exception.SOPGPException.UnsupportedOption if this option is not supported
-     */
-    Decrypt withPassword(String password)
-            throws SOPGPException.PasswordNotHumanReadable,
-            SOPGPException.UnsupportedOption;
-
-    /**
-     * Adds one or more decryption key.
-     *
-     * @param key input stream containing the key(s)
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.BadData if the {@link InputStream} does not provide an OpenPGP key
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
-     * @throws IOException in case of an IO error
-     */
-    Decrypt withKey(InputStream key)
-            throws SOPGPException.BadData,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            IOException;
-
-    /**
-     * Adds one or more decryption key.
-     *
-     * @param key byte array containing the key(s)
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an OpenPGP key
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
-     * @throws IOException in case of an IO error
-     */
-    default Decrypt withKey(byte[] key)
-            throws SOPGPException.BadData,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            IOException {
-        return withKey(new ByteArrayInputStream(key));
-    }
-
-    /**
-     * Provide the decryption password for the secret key.
-     *
-     * @param password password
-     * @return builder instance
-     * @throws sop.exception.SOPGPException.UnsupportedOption if the implementation does not support key passwords
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     */
-    default Decrypt withKeyPassword(String password)
-            throws SOPGPException.UnsupportedOption,
-            SOPGPException.PasswordNotHumanReadable {
-        return withKeyPassword(password.getBytes(UTF8Util.UTF8));
-    }
-
-    /**
-     * Provide the decryption password for the secret key.
-     *
-     * @param password password
-     * @return builder instance
-     * @throws sop.exception.SOPGPException.UnsupportedOption if the implementation does not support key passwords
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     */
-    Decrypt withKeyPassword(byte[] password)
-            throws SOPGPException.UnsupportedOption,
-            SOPGPException.PasswordNotHumanReadable;
-
-    /**
-     * Decrypts the given ciphertext, returning verification results and plaintext.
-     * @param ciphertext ciphertext
-     * @return ready with result
-     *
-     * @throws sop.exception.SOPGPException.BadData if the {@link InputStream} does not provide an OpenPGP message
-     * @throws sop.exception.SOPGPException.MissingArg if an argument required for decryption was not provided
-     * @throws sop.exception.SOPGPException.CannotDecrypt in case decryption fails for some reason
-     * @throws sop.exception.SOPGPException.KeyIsProtected if the decryption key cannot be unlocked (e.g. missing passphrase)
-     * @throws IOException in case of an IO error
-     */
-    ReadyWithResult<DecryptionResult> ciphertext(InputStream ciphertext)
-            throws SOPGPException.BadData,
-            SOPGPException.MissingArg,
-            SOPGPException.CannotDecrypt,
-            SOPGPException.KeyIsProtected,
-            IOException;
-
-    /**
-     * Decrypts the given ciphertext, returning verification results and plaintext.
-     * @param ciphertext ciphertext
-     * @return ready with result
-     *
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an encrypted OpenPGP message
-     * @throws sop.exception.SOPGPException.MissingArg in case of missing decryption method (password or key required)
-     * @throws sop.exception.SOPGPException.CannotDecrypt in case decryption fails for some reason
-     * @throws sop.exception.SOPGPException.KeyIsProtected if the decryption key cannot be unlocked (e.g. missing passphrase)
-     * @throws IOException in case of an IO error
-     */
-    default ReadyWithResult<DecryptionResult> ciphertext(byte[] ciphertext)
-            throws SOPGPException.BadData,
-            SOPGPException.MissingArg,
-            SOPGPException.CannotDecrypt,
-            SOPGPException.KeyIsProtected,
-            IOException {
-        return ciphertext(new ByteArrayInputStream(ciphertext));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/Decrypt.kt b/sop-java/src/main/kotlin/sop/operation/Decrypt.kt
new file mode 100644
index 0000000..9c24c54
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/Decrypt.kt
@@ -0,0 +1,169 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import java.util.*
+import sop.DecryptionResult
+import sop.ReadyWithResult
+import sop.SessionKey
+import sop.exception.SOPGPException.*
+import sop.util.UTF8Util
+
+interface Decrypt {
+
+    /**
+     * Makes the SOP consider signatures before this date invalid.
+     *
+     * @param timestamp timestamp
+     * @return builder instance
+     * @throws UnsupportedOption if this option is not supported
+     */
+    @Throws(UnsupportedOption::class) fun verifyNotBefore(timestamp: Date): Decrypt
+
+    /**
+     * Makes the SOP consider signatures after this date invalid.
+     *
+     * @param timestamp timestamp
+     * @return builder instance
+     * @throws UnsupportedOption if this option is not supported
+     */
+    @Throws(UnsupportedOption::class) fun verifyNotAfter(timestamp: Date): Decrypt
+
+    /**
+     * Adds one or more verification cert.
+     *
+     * @param cert input stream containing the cert(s)
+     * @return builder instance
+     * @throws BadData if the [InputStream] doesn't provide an OpenPGP certificate
+     * @throws UnsupportedAsymmetricAlgo if the cert uses an unsupported asymmetric algorithm
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, UnsupportedAsymmetricAlgo::class, IOException::class)
+    fun verifyWithCert(cert: InputStream): Decrypt
+
+    /**
+     * Adds one or more verification cert.
+     *
+     * @param cert byte array containing the cert(s)
+     * @return builder instance
+     * @throws BadData if the byte array doesn't contain an OpenPGP certificate
+     * @throws UnsupportedAsymmetricAlgo if the cert uses an unsupported asymmetric algorithm
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, UnsupportedAsymmetricAlgo::class, IOException::class)
+    fun verifyWithCert(cert: ByteArray): Decrypt = verifyWithCert(cert.inputStream())
+
+    /**
+     * Tries to decrypt with the given session key.
+     *
+     * @param sessionKey session key
+     * @return builder instance
+     * @throws UnsupportedOption if this option is not supported
+     */
+    @Throws(UnsupportedOption::class) fun withSessionKey(sessionKey: SessionKey): Decrypt
+
+    /**
+     * Tries to decrypt with the given password.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     * @throws UnsupportedOption if this option is not supported
+     */
+    @Throws(PasswordNotHumanReadable::class, UnsupportedOption::class)
+    fun withPassword(password: String): Decrypt
+
+    /**
+     * Adds one or more decryption key.
+     *
+     * @param key input stream containing the key(s)
+     * @return builder instance
+     * @throws BadData if the [InputStream] does not provide an OpenPGP key
+     * @throws UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, UnsupportedAsymmetricAlgo::class, IOException::class)
+    fun withKey(key: InputStream): Decrypt
+
+    /**
+     * Adds one or more decryption key.
+     *
+     * @param key byte array containing the key(s)
+     * @return builder instance
+     * @throws BadData if the byte array does not contain an OpenPGP key
+     * @throws UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, UnsupportedAsymmetricAlgo::class, IOException::class)
+    fun withKey(key: ByteArray): Decrypt {
+        return withKey(key.inputStream())
+    }
+
+    /**
+     * Provide the decryption password for the secret key.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws UnsupportedOption if the implementation does not support key passwords
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     */
+    @Throws(UnsupportedOption::class, PasswordNotHumanReadable::class)
+    fun withKeyPassword(password: String): Decrypt {
+        return withKeyPassword(password.toByteArray(UTF8Util.UTF8))
+    }
+
+    /**
+     * Provide the decryption password for the secret key.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws UnsupportedOption if the implementation does not support key passwords
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     */
+    @Throws(UnsupportedOption::class, PasswordNotHumanReadable::class)
+    fun withKeyPassword(password: ByteArray): Decrypt
+
+    /**
+     * Decrypts the given ciphertext, returning verification results and plaintext.
+     *
+     * @param ciphertext ciphertext
+     * @return ready with result
+     * @throws BadData if the [InputStream] does not provide an OpenPGP message
+     * @throws MissingArg if an argument required for decryption was not provided
+     * @throws CannotDecrypt in case decryption fails for some reason
+     * @throws KeyIsProtected if the decryption key cannot be unlocked (e.g. missing passphrase)
+     * @throws IOException in case of an IO error
+     */
+    @Throws(
+        BadData::class,
+        MissingArg::class,
+        CannotDecrypt::class,
+        KeyIsProtected::class,
+        IOException::class)
+    fun ciphertext(ciphertext: InputStream): ReadyWithResult<DecryptionResult>
+
+    /**
+     * Decrypts the given ciphertext, returning verification results and plaintext.
+     *
+     * @param ciphertext ciphertext
+     * @return ready with result
+     * @throws BadData if the byte array does not contain an encrypted OpenPGP message
+     * @throws MissingArg in case of missing decryption method (password or key required)
+     * @throws CannotDecrypt in case decryption fails for some reason
+     * @throws KeyIsProtected if the decryption key cannot be unlocked (e.g. missing passphrase)
+     * @throws IOException in case of an IO error
+     */
+    @Throws(
+        BadData::class,
+        MissingArg::class,
+        CannotDecrypt::class,
+        KeyIsProtected::class,
+        IOException::class)
+    fun ciphertext(ciphertext: ByteArray): ReadyWithResult<DecryptionResult> {
+        return ciphertext(ciphertext.inputStream())
+    }
+}

From 4dc1779a06be4aadffdd39855cb6e4da081cde00 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:10:06 +0100
Subject: [PATCH 20/46] Kotlin conversion: DetachedSign

---
 .../main/java/sop/operation/DetachedSign.java | 61 -------------------
 .../main/kotlin/sop/operation/DetachedSign.kt | 50 +++++++++++++++
 2 files changed, 50 insertions(+), 61 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/DetachedSign.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/DetachedSign.kt

diff --git a/sop-java/src/main/java/sop/operation/DetachedSign.java b/sop-java/src/main/java/sop/operation/DetachedSign.java
deleted file mode 100644
index 745077d..0000000
--- a/sop-java/src/main/java/sop/operation/DetachedSign.java
+++ /dev/null
@@ -1,61 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.ReadyWithResult;
-import sop.SigningResult;
-import sop.enums.SignAs;
-import sop.exception.SOPGPException;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-public interface DetachedSign extends AbstractSign<DetachedSign> {
-
-    /**
-     * Sets the signature mode.
-     * Note: This method has to be called before {@link #key(InputStream)} is called.
-     *
-     * @param mode signature mode
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.UnsupportedOption if this option is not supported
-     */
-    DetachedSign mode(SignAs mode)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Signs data.
-     *
-     * @param data input stream containing data
-     * @return ready
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.KeyIsProtected if at least one signing key cannot be unlocked
-     * @throws sop.exception.SOPGPException.ExpectedText if text data was expected, but binary data was encountered
-     */
-    ReadyWithResult<SigningResult> data(InputStream data)
-            throws IOException,
-            SOPGPException.KeyIsProtected,
-            SOPGPException.ExpectedText;
-
-    /**
-     * Signs data.
-     *
-     * @param data byte array containing data
-     * @return ready
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.KeyIsProtected if at least one signing key cannot be unlocked
-     * @throws sop.exception.SOPGPException.ExpectedText if text data was expected, but binary data was encountered
-     */
-    default ReadyWithResult<SigningResult> data(byte[] data)
-            throws IOException,
-            SOPGPException.KeyIsProtected,
-            SOPGPException.ExpectedText {
-        return data(new ByteArrayInputStream(data));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/DetachedSign.kt b/sop-java/src/main/kotlin/sop/operation/DetachedSign.kt
new file mode 100644
index 0000000..c0e62dd
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/DetachedSign.kt
@@ -0,0 +1,50 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import sop.ReadyWithResult
+import sop.SigningResult
+import sop.enums.SignAs
+import sop.exception.SOPGPException.*
+
+interface DetachedSign : AbstractSign<DetachedSign> {
+
+    /**
+     * Sets the signature mode. Note: This method has to be called before [key] is called.
+     *
+     * @param mode signature mode
+     * @return builder instance
+     * @throws UnsupportedOption if this option is not supported
+     */
+    @Throws(UnsupportedOption::class) fun mode(mode: SignAs): DetachedSign
+
+    /**
+     * Signs data.
+     *
+     * @param data input stream containing data
+     * @return ready
+     * @throws IOException in case of an IO error
+     * @throws KeyIsProtected if at least one signing key cannot be unlocked
+     * @throws ExpectedText if text data was expected, but binary data was encountered
+     */
+    @Throws(IOException::class, KeyIsProtected::class, ExpectedText::class)
+    fun data(data: InputStream): ReadyWithResult<SigningResult>
+
+    /**
+     * Signs data.
+     *
+     * @param data byte array containing data
+     * @return ready
+     * @throws IOException in case of an IO error
+     * @throws sop.exception.SOPGPException.KeyIsProtected if at least one signing key cannot be
+     *   unlocked
+     * @throws sop.exception.SOPGPException.ExpectedText if text data was expected, but binary data
+     *   was encountered
+     */
+    @Throws(IOException::class, KeyIsProtected::class, ExpectedText::class)
+    fun data(data: ByteArray): ReadyWithResult<SigningResult> = data(data.inputStream())
+}

From ee6975c7d3ab039b917aef476de44af7f542bef2 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:11:11 +0100
Subject: [PATCH 21/46] Decrypt: Use return statement

---
 sop-java/src/main/kotlin/sop/operation/Decrypt.kt | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/sop-java/src/main/kotlin/sop/operation/Decrypt.kt b/sop-java/src/main/kotlin/sop/operation/Decrypt.kt
index 9c24c54..ae228e9 100644
--- a/sop-java/src/main/kotlin/sop/operation/Decrypt.kt
+++ b/sop-java/src/main/kotlin/sop/operation/Decrypt.kt
@@ -99,9 +99,7 @@ interface Decrypt {
      * @throws IOException in case of an IO error
      */
     @Throws(BadData::class, UnsupportedAsymmetricAlgo::class, IOException::class)
-    fun withKey(key: ByteArray): Decrypt {
-        return withKey(key.inputStream())
-    }
+    fun withKey(key: ByteArray): Decrypt = withKey(key.inputStream())
 
     /**
      * Provide the decryption password for the secret key.
@@ -112,9 +110,8 @@ interface Decrypt {
      * @throws PasswordNotHumanReadable if the password is not human-readable
      */
     @Throws(UnsupportedOption::class, PasswordNotHumanReadable::class)
-    fun withKeyPassword(password: String): Decrypt {
-        return withKeyPassword(password.toByteArray(UTF8Util.UTF8))
-    }
+    fun withKeyPassword(password: String): Decrypt =
+        withKeyPassword(password.toByteArray(UTF8Util.UTF8))
 
     /**
      * Provide the decryption password for the secret key.
@@ -163,7 +160,6 @@ interface Decrypt {
         CannotDecrypt::class,
         KeyIsProtected::class,
         IOException::class)
-    fun ciphertext(ciphertext: ByteArray): ReadyWithResult<DecryptionResult> {
-        return ciphertext(ciphertext.inputStream())
-    }
+    fun ciphertext(ciphertext: ByteArray): ReadyWithResult<DecryptionResult> =
+        ciphertext(ciphertext.inputStream())
 }

From e681090757312dedcc90cc9fc35ee7f64118c99d Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:12:56 +0100
Subject: [PATCH 22/46] Kotlin conversion DetachedVerify

---
 .../java/sop/operation/DetachedVerify.java    | 45 -------------------
 .../kotlin/sop/operation/DetachedVerify.kt    | 36 +++++++++++++++
 2 files changed, 36 insertions(+), 45 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/DetachedVerify.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt

diff --git a/sop-java/src/main/java/sop/operation/DetachedVerify.java b/sop-java/src/main/java/sop/operation/DetachedVerify.java
deleted file mode 100644
index 9dee870..0000000
--- a/sop-java/src/main/java/sop/operation/DetachedVerify.java
+++ /dev/null
@@ -1,45 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.exception.SOPGPException;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-/**
- * API for verifying detached signatures.
- */
-public interface DetachedVerify extends AbstractVerify<DetachedVerify>, VerifySignatures {
-
-    /**
-     * Provides the detached signatures.
-     * @param signatures input stream containing encoded, detached signatures.
-     *
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.BadData if the input stream does not contain OpenPGP signatures
-     * @throws IOException in case of an IO error
-     */
-    VerifySignatures signatures(InputStream signatures)
-            throws SOPGPException.BadData,
-            IOException;
-
-    /**
-     * Provides the detached signatures.
-     * @param signatures byte array containing encoded, detached signatures.
-     *
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain OpenPGP signatures
-     * @throws IOException in case of an IO error
-     */
-    default VerifySignatures signatures(byte[] signatures)
-            throws SOPGPException.BadData,
-            IOException {
-        return signatures(new ByteArrayInputStream(signatures));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt b/sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt
new file mode 100644
index 0000000..2dd9218
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt
@@ -0,0 +1,36 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.ByteArrayInputStream
+import java.io.IOException
+import java.io.InputStream
+import sop.exception.SOPGPException.BadData
+
+interface DetachedVerify : AbstractVerify<DetachedVerify>, VerifySignatures {
+
+    /**
+     * Provides the detached signatures.
+     *
+     * @param signatures input stream containing encoded, detached signatures.
+     * @return builder instance
+     * @throws BadData if the input stream does not contain OpenPGP signatures
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class)
+    fun signatures(signatures: InputStream): VerifySignatures
+
+    /**
+     * Provides the detached signatures.
+     *
+     * @param signatures byte array containing encoded, detached signatures.
+     * @return builder instance
+     * @throws BadData if the byte array does not contain OpenPGP signatures
+     * @throws IOException in case of an IO error
+     */
+    @Throws(BadData::class, IOException::class)
+    fun signatures(signatures: ByteArray): VerifySignatures =
+        signatures(ByteArrayInputStream(signatures))
+}

From 41db9d2ac77d7b8e5c2fe79ae02ec36efb6bc240 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:15:56 +0100
Subject: [PATCH 23/46] Kotlin conversion: Encrypt

---
 .../src/main/java/sop/operation/Encrypt.java  | 193 ------------------
 .../src/main/kotlin/sop/operation/Encrypt.kt  | 166 +++++++++++++++
 2 files changed, 166 insertions(+), 193 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/Encrypt.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/Encrypt.kt

diff --git a/sop-java/src/main/java/sop/operation/Encrypt.java b/sop-java/src/main/java/sop/operation/Encrypt.java
deleted file mode 100644
index b380d32..0000000
--- a/sop-java/src/main/java/sop/operation/Encrypt.java
+++ /dev/null
@@ -1,193 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.Profile;
-import sop.Ready;
-import sop.enums.EncryptAs;
-import sop.exception.SOPGPException;
-import sop.util.UTF8Util;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-public interface Encrypt {
-
-    /**
-     * Disable ASCII armor encoding.
-     *
-     * @return builder instance
-     */
-    Encrypt noArmor();
-
-    /**
-     * Sets encryption mode.
-     *
-     * @param mode mode
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.UnsupportedOption if this option is not supported
-     */
-    Encrypt mode(EncryptAs mode)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Adds the signer key.
-     *
-     * @param key input stream containing the encoded signer key
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.KeyCannotSign if the key cannot be used for signing
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
-     * @throws sop.exception.SOPGPException.BadData if the {@link InputStream} does not contain an OpenPGP key
-     * @throws IOException in case of an IO error
-     */
-    Encrypt signWith(InputStream key)
-            throws SOPGPException.KeyCannotSign,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            SOPGPException.BadData,
-            IOException;
-
-    /**
-     * Adds the signer key.
-     *
-     * @param key byte array containing the encoded signer key
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.KeyCannotSign if the key cannot be used for signing
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an OpenPGP key
-     * @throws IOException in case of an IO error
-     */
-    default Encrypt signWith(byte[] key)
-            throws SOPGPException.KeyCannotSign,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            SOPGPException.BadData,
-            IOException {
-        return signWith(new ByteArrayInputStream(key));
-    }
-
-    /**
-     * Provide the password for the secret key used for signing.
-     *
-     * @param password password
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     * @throws sop.exception.SOPGPException.UnsupportedOption if key password are not supported
-     */
-    default Encrypt withKeyPassword(String password)
-            throws SOPGPException.PasswordNotHumanReadable,
-            SOPGPException.UnsupportedOption {
-        return withKeyPassword(password.getBytes(UTF8Util.UTF8));
-    }
-
-    /**
-     * Provide the password for the secret key used for signing.
-     *
-     * @param password password
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     * @throws sop.exception.SOPGPException.UnsupportedOption if key password are not supported
-     */
-    Encrypt withKeyPassword(byte[] password)
-            throws SOPGPException.PasswordNotHumanReadable,
-            SOPGPException.UnsupportedOption;
-
-    /**
-     * Encrypt with the given password.
-     *
-     * @param password password
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     * @throws sop.exception.SOPGPException.UnsupportedOption if this option is not supported
-     */
-    Encrypt withPassword(String password)
-            throws SOPGPException.PasswordNotHumanReadable,
-            SOPGPException.UnsupportedOption;
-
-    /**
-     * Encrypt with the given cert.
-     *
-     * @param cert input stream containing the encoded cert.
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.CertCannotEncrypt if the certificate is not encryption capable
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the certificate uses an unsupported asymmetric algorithm
-     * @throws sop.exception.SOPGPException.BadData if the {@link InputStream} does not contain an OpenPGP certificate
-     * @throws IOException in case of an IO error
-     */
-    Encrypt withCert(InputStream cert)
-            throws SOPGPException.CertCannotEncrypt,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            SOPGPException.BadData,
-            IOException;
-
-    /**
-     * Encrypt with the given cert.
-     *
-     * @param cert byte array containing the encoded cert.
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.CertCannotEncrypt if the certificate is not encryption capable
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the certificate uses an unsupported asymmetric algorithm
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an OpenPGP certificate
-     * @throws IOException in case of an IO error
-     */
-    default Encrypt withCert(byte[] cert)
-            throws SOPGPException.CertCannotEncrypt,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            SOPGPException.BadData,
-            IOException {
-        return withCert(new ByteArrayInputStream(cert));
-    }
-
-    /**
-     * Pass in a profile.
-     *
-     * @param profile profile
-     * @return builder instance
-     */
-    default Encrypt profile(Profile profile) {
-        return profile(profile.getName());
-    }
-
-    /**
-     * Pass in a profile identifier.
-     *
-     * @param profileName profile identifier
-     * @return builder instance
-     */
-    Encrypt profile(String profileName);
-
-    /**
-     * Encrypt the given data yielding the ciphertext.
-     * @param plaintext plaintext
-     * @return input stream containing the ciphertext
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.KeyIsProtected if at least one signing key cannot be unlocked
-     */
-    Ready plaintext(InputStream plaintext)
-            throws IOException,
-            SOPGPException.KeyIsProtected;
-
-    /**
-     * Encrypt the given data yielding the ciphertext.
-     * @param plaintext plaintext
-     * @return input stream containing the ciphertext
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.KeyIsProtected if at least one signing key cannot be unlocked
-     */
-    default Ready plaintext(byte[] plaintext)
-            throws IOException,
-            SOPGPException.KeyIsProtected {
-        return plaintext(new ByteArrayInputStream(plaintext));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/Encrypt.kt b/sop-java/src/main/kotlin/sop/operation/Encrypt.kt
new file mode 100644
index 0000000..ad30149
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/Encrypt.kt
@@ -0,0 +1,166 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.ByteArrayInputStream
+import java.io.IOException
+import java.io.InputStream
+import sop.Profile
+import sop.Ready
+import sop.enums.EncryptAs
+import sop.exception.SOPGPException.*
+import sop.util.UTF8Util
+
+interface Encrypt {
+
+    /**
+     * Disable ASCII armor encoding.
+     *
+     * @return builder instance
+     */
+    fun noArmor(): Encrypt
+
+    /**
+     * Sets encryption mode.
+     *
+     * @param mode mode
+     * @return builder instance
+     * @throws UnsupportedOption if this option is not supported
+     */
+    @Throws(UnsupportedOption::class) fun mode(mode: EncryptAs): Encrypt
+
+    /**
+     * Adds the signer key.
+     *
+     * @param key input stream containing the encoded signer key
+     * @return builder instance
+     * @throws KeyCannotSign if the key cannot be used for signing
+     * @throws UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
+     * @throws BadData if the [InputStream] does not contain an OpenPGP key
+     * @throws IOException in case of an IO error
+     */
+    @Throws(
+        KeyCannotSign::class, UnsupportedAsymmetricAlgo::class, BadData::class, IOException::class)
+    fun signWith(key: InputStream): Encrypt
+
+    /**
+     * Adds the signer key.
+     *
+     * @param key byte array containing the encoded signer key
+     * @return builder instance
+     * @throws KeyCannotSign if the key cannot be used for signing
+     * @throws UnsupportedAsymmetricAlgo if the key uses an unsupported asymmetric algorithm
+     * @throws BadData if the byte array does not contain an OpenPGP key
+     * @throws IOException in case of an IO error
+     */
+    @Throws(
+        KeyCannotSign::class, UnsupportedAsymmetricAlgo::class, BadData::class, IOException::class)
+    fun signWith(key: ByteArray): Encrypt = signWith(ByteArrayInputStream(key))
+
+    /**
+     * Provide the password for the secret key used for signing.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     * @throws UnsupportedOption if key password are not supported
+     */
+    @Throws(PasswordNotHumanReadable::class, UnsupportedOption::class)
+    fun withKeyPassword(password: String): Encrypt =
+        withKeyPassword(password.toByteArray(UTF8Util.UTF8))
+
+    /**
+     * Provide the password for the secret key used for signing.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     * @throws UnsupportedOption if key password are not supported
+     */
+    @Throws(PasswordNotHumanReadable::class, UnsupportedOption::class)
+    fun withKeyPassword(password: ByteArray): Encrypt
+
+    /**
+     * Encrypt with the given password.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     * @throws UnsupportedOption if this option is not supported
+     */
+    @Throws(PasswordNotHumanReadable::class, UnsupportedOption::class)
+    fun withPassword(password: String): Encrypt
+
+    /**
+     * Encrypt with the given cert.
+     *
+     * @param cert input stream containing the encoded cert.
+     * @return builder instance
+     * @throws CertCannotEncrypt if the certificate is not encryption capable
+     * @throws UnsupportedAsymmetricAlgo if the certificate uses an unsupported asymmetric algorithm
+     * @throws BadData if the [InputStream] does not contain an OpenPGP certificate
+     * @throws IOException in case of an IO error
+     */
+    @Throws(
+        CertCannotEncrypt::class,
+        UnsupportedAsymmetricAlgo::class,
+        BadData::class,
+        IOException::class)
+    fun withCert(cert: InputStream): Encrypt
+
+    /**
+     * Encrypt with the given cert.
+     *
+     * @param cert byte array containing the encoded cert.
+     * @return builder instance
+     * @throws CertCannotEncrypt if the certificate is not encryption capable
+     * @throws UnsupportedAsymmetricAlgo if the certificate uses an unsupported asymmetric algorithm
+     * @throws BadData if the byte array does not contain an OpenPGP certificate
+     * @throws IOException in case of an IO error
+     */
+    @Throws(
+        CertCannotEncrypt::class,
+        UnsupportedAsymmetricAlgo::class,
+        BadData::class,
+        IOException::class)
+    fun withCert(cert: ByteArray): Encrypt = withCert(ByteArrayInputStream(cert))
+
+    /**
+     * Pass in a profile.
+     *
+     * @param profile profile
+     * @return builder instance
+     */
+    fun profile(profile: Profile): Encrypt = profile(profile.name)
+
+    /**
+     * Pass in a profile identifier.
+     *
+     * @param profileName profile identifier
+     * @return builder instance
+     */
+    fun profile(profileName: String): Encrypt
+
+    /**
+     * Encrypt the given data yielding the ciphertext.
+     *
+     * @param plaintext plaintext
+     * @return input stream containing the ciphertext
+     * @throws IOException in case of an IO error
+     * @throws KeyIsProtected if at least one signing key cannot be unlocked
+     */
+    @Throws(IOException::class, KeyIsProtected::class) fun plaintext(plaintext: InputStream): Ready
+
+    /**
+     * Encrypt the given data yielding the ciphertext.
+     *
+     * @param plaintext plaintext
+     * @return input stream containing the ciphertext
+     * @throws IOException in case of an IO error
+     * @throws KeyIsProtected if at least one signing key cannot be unlocked
+     */
+    @Throws(IOException::class, KeyIsProtected::class)
+    fun plaintext(plaintext: ByteArray): Ready = plaintext(ByteArrayInputStream(plaintext))
+}

From 653675f730788593566aba75879870d4e39f652e Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:17:12 +0100
Subject: [PATCH 24/46] Kotlin conversion: ExtractCert

---
 .../main/java/sop/operation/ExtractCert.java  | 50 -------------------
 .../main/kotlin/sop/operation/ExtractCert.kt  | 42 ++++++++++++++++
 2 files changed, 42 insertions(+), 50 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/ExtractCert.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/ExtractCert.kt

diff --git a/sop-java/src/main/java/sop/operation/ExtractCert.java b/sop-java/src/main/java/sop/operation/ExtractCert.java
deleted file mode 100644
index a862d33..0000000
--- a/sop-java/src/main/java/sop/operation/ExtractCert.java
+++ /dev/null
@@ -1,50 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-import sop.Ready;
-import sop.exception.SOPGPException;
-
-public interface ExtractCert {
-
-    /**
-     * Disable ASCII armor encoding.
-     *
-     * @return builder instance
-     */
-    ExtractCert noArmor();
-
-    /**
-     * Extract the cert(s) from the provided key(s).
-     *
-     * @param keyInputStream input stream containing the encoding of one or more OpenPGP keys
-     * @return result containing the encoding of the keys certs
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.BadData if the {@link InputStream} does not contain an OpenPGP key
-     */
-    Ready key(InputStream keyInputStream)
-            throws IOException,
-            SOPGPException.BadData;
-
-    /**
-     * Extract the cert(s) from the provided key(s).
-     *
-     * @param key byte array containing the encoding of one or more OpenPGP key
-     * @return result containing the encoding of the keys certs
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain an OpenPGP key
-     */
-    default Ready key(byte[] key)
-            throws IOException,
-            SOPGPException.BadData {
-        return key(new ByteArrayInputStream(key));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/ExtractCert.kt b/sop-java/src/main/kotlin/sop/operation/ExtractCert.kt
new file mode 100644
index 0000000..bd48e08
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/ExtractCert.kt
@@ -0,0 +1,42 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.ByteArrayInputStream
+import java.io.IOException
+import java.io.InputStream
+import sop.Ready
+import sop.exception.SOPGPException.BadData
+
+interface ExtractCert {
+
+    /**
+     * Disable ASCII armor encoding.
+     *
+     * @return builder instance
+     */
+    fun noArmor(): ExtractCert
+
+    /**
+     * Extract the cert(s) from the provided key(s).
+     *
+     * @param keyInputStream input stream containing the encoding of one or more OpenPGP keys
+     * @return result containing the encoding of the keys certs
+     * @throws IOException in case of an IO error
+     * @throws BadData if the [InputStream] does not contain an OpenPGP key
+     */
+    @Throws(IOException::class, BadData::class) fun key(keyInputStream: InputStream): Ready
+
+    /**
+     * Extract the cert(s) from the provided key(s).
+     *
+     * @param key byte array containing the encoding of one or more OpenPGP key
+     * @return result containing the encoding of the keys certs
+     * @throws IOException in case of an IO error
+     * @throws BadData if the byte array does not contain an OpenPGP key
+     */
+    @Throws(IOException::class, BadData::class)
+    fun key(key: ByteArray): Ready = key(ByteArrayInputStream(key))
+}

From 3e6ebe1cc44968b1ecad4d6244fc43f874a2aa64 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:19:08 +0100
Subject: [PATCH 25/46] Kotlin conversion: GenerateKey

---
 .../main/java/sop/operation/GenerateKey.java  | 103 ------------------
 .../main/kotlin/sop/operation/GenerateKey.kt  |  91 ++++++++++++++++
 2 files changed, 91 insertions(+), 103 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/GenerateKey.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/GenerateKey.kt

diff --git a/sop-java/src/main/java/sop/operation/GenerateKey.java b/sop-java/src/main/java/sop/operation/GenerateKey.java
deleted file mode 100644
index 77afea1..0000000
--- a/sop-java/src/main/java/sop/operation/GenerateKey.java
+++ /dev/null
@@ -1,103 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.nio.charset.CharacterCodingException;
-
-import sop.Profile;
-import sop.Ready;
-import sop.exception.SOPGPException;
-import sop.util.UTF8Util;
-
-public interface GenerateKey {
-
-    /**
-     * Disable ASCII armor encoding.
-     *
-     * @return builder instance
-     */
-    GenerateKey noArmor();
-
-    /**
-     * Adds a user-id.
-     *
-     * @param userId user-id
-     * @return builder instance
-     */
-    GenerateKey userId(String userId);
-
-    /**
-     * Set a password for the key.
-     *
-     * @param password password to protect the key
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.UnsupportedOption if key passwords are not supported
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     */
-    GenerateKey withKeyPassword(String password)
-            throws SOPGPException.PasswordNotHumanReadable,
-            SOPGPException.UnsupportedOption;
-
-    /**
-     * Set a password for the key.
-     *
-     * @param password password to protect the key
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     * @throws sop.exception.SOPGPException.UnsupportedOption if key passwords are not supported
-     */
-    default GenerateKey withKeyPassword(byte[] password)
-            throws SOPGPException.PasswordNotHumanReadable,
-            SOPGPException.UnsupportedOption {
-        try {
-            return withKeyPassword(UTF8Util.decodeUTF8(password));
-        } catch (CharacterCodingException e) {
-            throw new SOPGPException.PasswordNotHumanReadable();
-        }
-    }
-
-    /**
-     * Pass in a profile.
-     *
-     * @param profile profile
-     * @return builder instance
-     */
-    default GenerateKey profile(Profile profile) {
-        return profile(profile.getName());
-    }
-
-    /**
-     * Pass in a profile identifier.
-     *
-     * @param profile profile identifier
-     * @return builder instance
-     */
-    GenerateKey profile(String profile);
-
-    /**
-     * If this options is set, the generated key will not be capable of encryption / decryption.
-     *
-     * @return builder instance
-     */
-    GenerateKey signingOnly();
-
-    /**
-     * Generate the OpenPGP key and return it encoded as an {@link InputStream}.
-     *
-     * @return key
-     *
-     * @throws sop.exception.SOPGPException.MissingArg if no user-id was provided
-     * @throws sop.exception.SOPGPException.UnsupportedAsymmetricAlgo if the generated key uses an unsupported asymmetric algorithm
-     * @throws IOException in case of an IO error
-     */
-    Ready generate()
-            throws SOPGPException.MissingArg,
-            SOPGPException.UnsupportedAsymmetricAlgo,
-            IOException;
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/GenerateKey.kt b/sop-java/src/main/kotlin/sop/operation/GenerateKey.kt
new file mode 100644
index 0000000..3b83b99
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/GenerateKey.kt
@@ -0,0 +1,91 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import sop.Profile
+import sop.Ready
+import sop.exception.SOPGPException.*
+import sop.util.UTF8Util
+
+interface GenerateKey {
+
+    /**
+     * Disable ASCII armor encoding.
+     *
+     * @return builder instance
+     */
+    fun noArmor(): GenerateKey
+
+    /**
+     * Adds a user-id.
+     *
+     * @param userId user-id
+     * @return builder instance
+     */
+    fun userId(userId: String): GenerateKey
+
+    /**
+     * Set a password for the key.
+     *
+     * @param password password to protect the key
+     * @return builder instance
+     * @throws UnsupportedOption if key passwords are not supported
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     */
+    @Throws(PasswordNotHumanReadable::class, UnsupportedOption::class)
+    fun withKeyPassword(password: String): GenerateKey
+
+    /**
+     * Set a password for the key.
+     *
+     * @param password password to protect the key
+     * @return builder instance
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     * @throws UnsupportedOption if key passwords are not supported
+     */
+    @Throws(PasswordNotHumanReadable::class, UnsupportedOption::class)
+    fun withKeyPassword(password: ByteArray): GenerateKey =
+        try {
+            withKeyPassword(UTF8Util.decodeUTF8(password))
+        } catch (e: CharacterCodingException) {
+            throw PasswordNotHumanReadable()
+        }
+
+    /**
+     * Pass in a profile.
+     *
+     * @param profile profile
+     * @return builder instance
+     */
+    fun profile(profile: Profile): GenerateKey = profile(profile.name)
+
+    /**
+     * Pass in a profile identifier.
+     *
+     * @param profile profile identifier
+     * @return builder instance
+     */
+    fun profile(profile: String): GenerateKey
+
+    /**
+     * If this options is set, the generated key will not be capable of encryption / decryption.
+     *
+     * @return builder instance
+     */
+    fun signingOnly(): GenerateKey
+
+    /**
+     * Generate the OpenPGP key and return it encoded as an [InputStream].
+     *
+     * @return key
+     * @throws MissingArg if no user-id was provided
+     * @throws UnsupportedAsymmetricAlgo if the generated key uses an unsupported asymmetric
+     *   algorithm
+     * @throws IOException in case of an IO error
+     */
+    @Throws(MissingArg::class, UnsupportedAsymmetricAlgo::class, IOException::class)
+    fun generate(): Ready
+}

From 8df4a520bdb6c2e37ea81cf71f0cf7e8b422eb7e Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:20:29 +0100
Subject: [PATCH 26/46] Kotlin conversion: InlineDetach

---
 .../main/java/sop/operation/InlineDetach.java | 52 -------------------
 .../main/kotlin/sop/operation/InlineDetach.kt | 43 +++++++++++++++
 2 files changed, 43 insertions(+), 52 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/InlineDetach.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/InlineDetach.kt

diff --git a/sop-java/src/main/java/sop/operation/InlineDetach.java b/sop-java/src/main/java/sop/operation/InlineDetach.java
deleted file mode 100644
index aba40b1..0000000
--- a/sop-java/src/main/java/sop/operation/InlineDetach.java
+++ /dev/null
@@ -1,52 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-import sop.ReadyWithResult;
-import sop.Signatures;
-import sop.exception.SOPGPException;
-
-/**
- * Split cleartext signed messages up into data and signatures.
- */
-public interface InlineDetach {
-
-    /**
-     * Do not wrap the signatures in ASCII armor.
-     * @return builder
-     */
-    InlineDetach noArmor();
-
-    /**
-     * Detach the provided signed message from its signatures.
-     *
-     * @param messageInputStream input stream containing the signed message
-     * @return result containing the detached message
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.BadData if the input stream does not contain a signed message
-     */
-    ReadyWithResult<Signatures> message(InputStream messageInputStream)
-            throws IOException,
-            SOPGPException.BadData;
-
-    /**
-     * Detach the provided cleartext signed message from its signatures.
-     *
-     * @param message byte array containing the signed message
-     * @return result containing the detached message
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.BadData if the byte array does not contain a signed message
-     */
-    default ReadyWithResult<Signatures> message(byte[] message)
-            throws IOException,
-            SOPGPException.BadData {
-        return message(new ByteArrayInputStream(message));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/InlineDetach.kt b/sop-java/src/main/kotlin/sop/operation/InlineDetach.kt
new file mode 100644
index 0000000..941a9bf
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/InlineDetach.kt
@@ -0,0 +1,43 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import sop.ReadyWithResult
+import sop.Signatures
+import sop.exception.SOPGPException.BadData
+
+interface InlineDetach {
+
+    /**
+     * Do not wrap the signatures in ASCII armor.
+     *
+     * @return builder
+     */
+    fun noArmor(): InlineDetach
+
+    /**
+     * Detach the provided signed message from its signatures.
+     *
+     * @param messageInputStream input stream containing the signed message
+     * @return result containing the detached message
+     * @throws IOException in case of an IO error
+     * @throws BadData if the input stream does not contain a signed message
+     */
+    @Throws(IOException::class, BadData::class)
+    fun message(messageInputStream: InputStream): ReadyWithResult<Signatures>
+
+    /**
+     * Detach the provided cleartext signed message from its signatures.
+     *
+     * @param message byte array containing the signed message
+     * @return result containing the detached message
+     * @throws IOException in case of an IO error
+     * @throws BadData if the byte array does not contain a signed message
+     */
+    @Throws(IOException::class, BadData::class)
+    fun message(message: ByteArray): ReadyWithResult<Signatures> = message(message.inputStream())
+}

From 9283f81c56662d63c565dfd2aaac14868c4bbc3d Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:22:12 +0100
Subject: [PATCH 27/46] Replace ByteArrayInputStream with inputStream()

---
 sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt | 4 +---
 sop-java/src/main/kotlin/sop/operation/Encrypt.kt        | 7 +++----
 sop-java/src/main/kotlin/sop/operation/ExtractCert.kt    | 3 +--
 3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt b/sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt
index 2dd9218..d899b54 100644
--- a/sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt
+++ b/sop-java/src/main/kotlin/sop/operation/DetachedVerify.kt
@@ -4,7 +4,6 @@
 
 package sop.operation
 
-import java.io.ByteArrayInputStream
 import java.io.IOException
 import java.io.InputStream
 import sop.exception.SOPGPException.BadData
@@ -31,6 +30,5 @@ interface DetachedVerify : AbstractVerify<DetachedVerify>, VerifySignatures {
      * @throws IOException in case of an IO error
      */
     @Throws(BadData::class, IOException::class)
-    fun signatures(signatures: ByteArray): VerifySignatures =
-        signatures(ByteArrayInputStream(signatures))
+    fun signatures(signatures: ByteArray): VerifySignatures = signatures(signatures.inputStream())
 }
diff --git a/sop-java/src/main/kotlin/sop/operation/Encrypt.kt b/sop-java/src/main/kotlin/sop/operation/Encrypt.kt
index ad30149..0daebee 100644
--- a/sop-java/src/main/kotlin/sop/operation/Encrypt.kt
+++ b/sop-java/src/main/kotlin/sop/operation/Encrypt.kt
@@ -4,7 +4,6 @@
 
 package sop.operation
 
-import java.io.ByteArrayInputStream
 import java.io.IOException
 import java.io.InputStream
 import sop.Profile
@@ -57,7 +56,7 @@ interface Encrypt {
      */
     @Throws(
         KeyCannotSign::class, UnsupportedAsymmetricAlgo::class, BadData::class, IOException::class)
-    fun signWith(key: ByteArray): Encrypt = signWith(ByteArrayInputStream(key))
+    fun signWith(key: ByteArray): Encrypt = signWith(key.inputStream())
 
     /**
      * Provide the password for the secret key used for signing.
@@ -125,7 +124,7 @@ interface Encrypt {
         UnsupportedAsymmetricAlgo::class,
         BadData::class,
         IOException::class)
-    fun withCert(cert: ByteArray): Encrypt = withCert(ByteArrayInputStream(cert))
+    fun withCert(cert: ByteArray): Encrypt = withCert(cert.inputStream())
 
     /**
      * Pass in a profile.
@@ -162,5 +161,5 @@ interface Encrypt {
      * @throws KeyIsProtected if at least one signing key cannot be unlocked
      */
     @Throws(IOException::class, KeyIsProtected::class)
-    fun plaintext(plaintext: ByteArray): Ready = plaintext(ByteArrayInputStream(plaintext))
+    fun plaintext(plaintext: ByteArray): Ready = plaintext(plaintext.inputStream())
 }
diff --git a/sop-java/src/main/kotlin/sop/operation/ExtractCert.kt b/sop-java/src/main/kotlin/sop/operation/ExtractCert.kt
index bd48e08..e2ce1cc 100644
--- a/sop-java/src/main/kotlin/sop/operation/ExtractCert.kt
+++ b/sop-java/src/main/kotlin/sop/operation/ExtractCert.kt
@@ -4,7 +4,6 @@
 
 package sop.operation
 
-import java.io.ByteArrayInputStream
 import java.io.IOException
 import java.io.InputStream
 import sop.Ready
@@ -38,5 +37,5 @@ interface ExtractCert {
      * @throws BadData if the byte array does not contain an OpenPGP key
      */
     @Throws(IOException::class, BadData::class)
-    fun key(key: ByteArray): Ready = key(ByteArrayInputStream(key))
+    fun key(key: ByteArray): Ready = key(key.inputStream())
 }

From be0ceb0886a9b6a51b51a4519b4098e761ad0cf3 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:25:25 +0100
Subject: [PATCH 28/46] Kotlin conversion: InlineSign

---
 .../main/java/sop/operation/InlineSign.java   | 60 -------------------
 .../main/kotlin/sop/operation/InlineSign.kt   | 47 +++++++++++++++
 2 files changed, 47 insertions(+), 60 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/InlineSign.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/InlineSign.kt

diff --git a/sop-java/src/main/java/sop/operation/InlineSign.java b/sop-java/src/main/java/sop/operation/InlineSign.java
deleted file mode 100644
index d45aebd..0000000
--- a/sop-java/src/main/java/sop/operation/InlineSign.java
+++ /dev/null
@@ -1,60 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.Ready;
-import sop.enums.InlineSignAs;
-import sop.exception.SOPGPException;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-
-public interface InlineSign extends AbstractSign<InlineSign> {
-
-    /**
-     * Sets the signature mode.
-     * Note: This method has to be called before {@link #key(InputStream)} is called.
-     *
-     * @param mode signature mode
-     * @return builder instance
-     *
-     * @throws sop.exception.SOPGPException.UnsupportedOption if this option is not supported
-     */
-    InlineSign mode(InlineSignAs mode)
-            throws SOPGPException.UnsupportedOption;
-
-    /**
-     * Signs data.
-     *
-     * @param data input stream containing data
-     * @return ready
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.KeyIsProtected if at least one signing key cannot be unlocked
-     * @throws sop.exception.SOPGPException.ExpectedText if text data was expected, but binary data was encountered
-     */
-    Ready data(InputStream data)
-            throws IOException,
-            SOPGPException.KeyIsProtected,
-            SOPGPException.ExpectedText;
-
-    /**
-     * Signs data.
-     *
-     * @param data byte array containing data
-     * @return ready
-     *
-     * @throws IOException in case of an IO error
-     * @throws sop.exception.SOPGPException.KeyIsProtected if at least one signing key cannot be unlocked
-     * @throws sop.exception.SOPGPException.ExpectedText if text data was expected, but binary data was encountered
-     */
-    default Ready data(byte[] data)
-            throws IOException,
-            SOPGPException.KeyIsProtected,
-            SOPGPException.ExpectedText {
-        return data(new ByteArrayInputStream(data));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/InlineSign.kt b/sop-java/src/main/kotlin/sop/operation/InlineSign.kt
new file mode 100644
index 0000000..11b5668
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/InlineSign.kt
@@ -0,0 +1,47 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import sop.Ready
+import sop.enums.InlineSignAs
+import sop.exception.SOPGPException.*
+
+interface InlineSign : AbstractSign<InlineSign> {
+
+    /**
+     * Sets the signature mode. Note: This method has to be called before [.key] is called.
+     *
+     * @param mode signature mode
+     * @return builder instance
+     * @throws UnsupportedOption if this option is not supported
+     */
+    @Throws(UnsupportedOption::class) fun mode(mode: InlineSignAs): InlineSign
+
+    /**
+     * Signs data.
+     *
+     * @param data input stream containing data
+     * @return ready
+     * @throws IOException in case of an IO error
+     * @throws KeyIsProtected if at least one signing key cannot be unlocked
+     * @throws ExpectedText if text data was expected, but binary data was encountered
+     */
+    @Throws(IOException::class, KeyIsProtected::class, ExpectedText::class)
+    fun data(data: InputStream): Ready
+
+    /**
+     * Signs data.
+     *
+     * @param data byte array containing data
+     * @return ready
+     * @throws IOException in case of an IO error
+     * @throws KeyIsProtected if at least one signing key cannot be unlocked
+     * @throws ExpectedText if text data was expected, but binary data was encountered
+     */
+    @Throws(IOException::class, KeyIsProtected::class, ExpectedText::class)
+    fun data(data: ByteArray): Ready = data(data.inputStream())
+}

From 6c14f249bb66ba8ca019c8235fe2c21112baf876 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:25:47 +0100
Subject: [PATCH 29/46] Kotlin conversion: InlineVerify

---
 .../main/java/sop/operation/InlineVerify.java | 54 -------------------
 .../main/kotlin/sop/operation/InlineVerify.kt | 42 +++++++++++++++
 2 files changed, 42 insertions(+), 54 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/InlineVerify.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/InlineVerify.kt

diff --git a/sop-java/src/main/java/sop/operation/InlineVerify.java b/sop-java/src/main/java/sop/operation/InlineVerify.java
deleted file mode 100644
index ac662a0..0000000
--- a/sop-java/src/main/java/sop/operation/InlineVerify.java
+++ /dev/null
@@ -1,54 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.ReadyWithResult;
-import sop.Verification;
-import sop.exception.SOPGPException;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.List;
-
-/**
- * API for verification of inline-signed messages.
- */
-public interface InlineVerify extends AbstractVerify<InlineVerify> {
-
-    /**
-     * Provide the inline-signed data.
-     * The result can be used to write the plaintext message out and to get the verifications.
-     *
-     * @param data signed data
-     * @return list of signature verifications
-     *
-     * @throws IOException in case of an IO error
-     * @throws SOPGPException.NoSignature when no signature is found
-     * @throws SOPGPException.BadData when the data is invalid OpenPGP data
-     */
-    ReadyWithResult<List<Verification>> data(InputStream data)
-            throws IOException,
-            SOPGPException.NoSignature,
-            SOPGPException.BadData;
-
-    /**
-     * Provide the inline-signed data.
-     * The result can be used to write the plaintext message out and to get the verifications.
-     *
-     * @param data signed data
-     * @return list of signature verifications
-     *
-     * @throws IOException in case of an IO error
-     * @throws SOPGPException.NoSignature when no signature is found
-     * @throws SOPGPException.BadData when the data is invalid OpenPGP data
-     */
-    default ReadyWithResult<List<Verification>> data(byte[] data)
-            throws IOException,
-            SOPGPException.NoSignature,
-            SOPGPException.BadData {
-        return data(new ByteArrayInputStream(data));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/InlineVerify.kt b/sop-java/src/main/kotlin/sop/operation/InlineVerify.kt
new file mode 100644
index 0000000..c16b269
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/InlineVerify.kt
@@ -0,0 +1,42 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import sop.ReadyWithResult
+import sop.Verification
+import sop.exception.SOPGPException.BadData
+import sop.exception.SOPGPException.NoSignature
+
+/** API for verification of inline-signed messages. */
+interface InlineVerify : AbstractVerify<InlineVerify> {
+
+    /**
+     * Provide the inline-signed data. The result can be used to write the plaintext message out and
+     * to get the verifications.
+     *
+     * @param data signed data
+     * @return list of signature verifications
+     * @throws IOException in case of an IO error
+     * @throws NoSignature when no signature is found
+     * @throws BadData when the data is invalid OpenPGP data
+     */
+    @Throws(IOException::class, NoSignature::class, BadData::class)
+    fun data(data: InputStream): ReadyWithResult<List<Verification>>
+
+    /**
+     * Provide the inline-signed data. The result can be used to write the plaintext message out and
+     * to get the verifications.
+     *
+     * @param data signed data
+     * @return list of signature verifications
+     * @throws IOException in case of an IO error
+     * @throws NoSignature when no signature is found
+     * @throws BadData when the data is invalid OpenPGP data
+     */
+    @Throws(IOException::class, NoSignature::class, BadData::class)
+    fun data(data: ByteArray): ReadyWithResult<List<Verification>> = data(data.inputStream())
+}

From 145cadef4f7557a52529eaea1a04eb3bcb484868 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:27:17 +0100
Subject: [PATCH 30/46] Kotlin conversion: ListProfiles

---
 .../main/java/sop/operation/ListProfiles.java | 43 -------------------
 .../main/kotlin/sop/operation/ListProfiles.kt | 34 +++++++++++++++
 2 files changed, 34 insertions(+), 43 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/ListProfiles.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/ListProfiles.kt

diff --git a/sop-java/src/main/java/sop/operation/ListProfiles.java b/sop-java/src/main/java/sop/operation/ListProfiles.java
deleted file mode 100644
index 0c17bd6..0000000
--- a/sop-java/src/main/java/sop/operation/ListProfiles.java
+++ /dev/null
@@ -1,43 +0,0 @@
-// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.Profile;
-
-import java.util.List;
-
-/**
- * Subcommand to list supported profiles of other subcommands.
- */
-public interface ListProfiles {
-
-    /**
-     * Provide the name of the subcommand for which profiles shall be listed.
-     * The returned list of profiles MUST NOT contain more than 4 entries.
-     *
-     * @param command command name (e.g. <pre>generate-key</pre>)
-     * @return list of profiles.
-     */
-    List<Profile> subcommand(String command);
-
-    /**
-     * Return a list of {@link Profile Profiles} supported by the {@link GenerateKey} implementation.
-     *
-     * @return profiles
-     */
-    default List<Profile> generateKey() {
-        return subcommand("generate-key");
-    }
-
-    /**
-     * Return a list of {@link Profile Profiles} supported by the {@link Encrypt} implementation.
-     *
-     * @return profiles
-     */
-    default List<Profile> encrypt() {
-        return subcommand("encrypt");
-    }
-
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/ListProfiles.kt b/sop-java/src/main/kotlin/sop/operation/ListProfiles.kt
new file mode 100644
index 0000000..315faf2
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/ListProfiles.kt
@@ -0,0 +1,34 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import sop.Profile
+
+/** Subcommand to list supported profiles of other subcommands. */
+interface ListProfiles {
+
+    /**
+     * Provide the name of the subcommand for which profiles shall be listed. The returned list of
+     * profiles MUST NOT contain more than 4 entries.
+     *
+     * @param command command name (e.g. `generate-key`)
+     * @return list of profiles.
+     */
+    fun subcommand(command: String): List<Profile>
+
+    /**
+     * Return a list of [Profiles][Profile] supported by the [GenerateKey] implementation.
+     *
+     * @return profiles
+     */
+    fun generateKey(): List<Profile> = subcommand("generate-key")
+
+    /**
+     * Return a list of [Profiles][Profile] supported by the [Encrypt] implementation.
+     *
+     * @return profiles
+     */
+    fun encrypt(): List<Profile> = subcommand("encrypt")
+}

From 0ee4638bebf88f28fc434f9c78b6fef45c8a877a Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:28:59 +0100
Subject: [PATCH 31/46] Kotlin conversion: RevokeKey

---
 .../main/java/sop/operation/RevokeKey.java    | 54 -------------------
 .../main/kotlin/sop/operation/RevokeKey.kt    | 48 +++++++++++++++++
 2 files changed, 48 insertions(+), 54 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/RevokeKey.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/RevokeKey.kt

diff --git a/sop-java/src/main/java/sop/operation/RevokeKey.java b/sop-java/src/main/java/sop/operation/RevokeKey.java
deleted file mode 100644
index 3ceb5b3..0000000
--- a/sop-java/src/main/java/sop/operation/RevokeKey.java
+++ /dev/null
@@ -1,54 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import sop.Ready;
-import sop.exception.SOPGPException;
-import sop.util.UTF8Util;
-
-import java.io.ByteArrayInputStream;
-import java.io.InputStream;
-
-public interface RevokeKey {
-
-    /**
-     * Disable ASCII armor encoding.
-     *
-     * @return builder instance
-     */
-    RevokeKey noArmor();
-
-    /**
-     * Provide the decryption password for the secret key.
-     *
-     * @param password password
-     * @return builder instance
-     * @throws SOPGPException.UnsupportedOption if the implementation does not support key passwords
-     * @throws SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     */
-    default RevokeKey withKeyPassword(String password)
-            throws SOPGPException.UnsupportedOption,
-            SOPGPException.PasswordNotHumanReadable {
-        return withKeyPassword(password.getBytes(UTF8Util.UTF8));
-    }
-
-    /**
-     * Provide the decryption password for the secret key.
-     *
-     * @param password password
-     * @return builder instance
-     * @throws SOPGPException.UnsupportedOption if the implementation does not support key passwords
-     * @throws SOPGPException.PasswordNotHumanReadable if the password is not human-readable
-     */
-    RevokeKey withKeyPassword(byte[] password)
-            throws SOPGPException.UnsupportedOption,
-            SOPGPException.PasswordNotHumanReadable;
-
-    default Ready keys(byte[] bytes) {
-        return keys(new ByteArrayInputStream(bytes));
-    }
-
-    Ready keys(InputStream keys);
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/RevokeKey.kt b/sop-java/src/main/kotlin/sop/operation/RevokeKey.kt
new file mode 100644
index 0000000..f3cbe5c
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/RevokeKey.kt
@@ -0,0 +1,48 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.InputStream
+import sop.Ready
+import sop.exception.SOPGPException.PasswordNotHumanReadable
+import sop.exception.SOPGPException.UnsupportedOption
+import sop.util.UTF8Util
+
+interface RevokeKey {
+
+    /**
+     * Disable ASCII armor encoding.
+     *
+     * @return builder instance
+     */
+    fun noArmor(): RevokeKey
+
+    /**
+     * Provide the decryption password for the secret key.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws UnsupportedOption if the implementation does not support key passwords
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     */
+    @Throws(UnsupportedOption::class, PasswordNotHumanReadable::class)
+    fun withKeyPassword(password: String): RevokeKey =
+        withKeyPassword(password.toByteArray(UTF8Util.UTF8))
+
+    /**
+     * Provide the decryption password for the secret key.
+     *
+     * @param password password
+     * @return builder instance
+     * @throws UnsupportedOption if the implementation does not support key passwords
+     * @throws PasswordNotHumanReadable if the password is not human-readable
+     */
+    @Throws(UnsupportedOption::class, PasswordNotHumanReadable::class)
+    fun withKeyPassword(password: ByteArray): RevokeKey
+
+    fun keys(bytes: ByteArray): Ready = keys(bytes.inputStream())
+
+    fun keys(keys: InputStream): Ready
+}

From a8c2e72ef589bdeea16df71c2901842b6fdd5220 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:30:24 +0100
Subject: [PATCH 32/46] Kotlin conversion: VerifySignatures

---
 .../java/sop/operation/VerifySignatures.java  | 46 -------------------
 .../kotlin/sop/operation/VerifySignatures.kt  | 38 +++++++++++++++
 2 files changed, 38 insertions(+), 46 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/VerifySignatures.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/VerifySignatures.kt

diff --git a/sop-java/src/main/java/sop/operation/VerifySignatures.java b/sop-java/src/main/java/sop/operation/VerifySignatures.java
deleted file mode 100644
index 5181514..0000000
--- a/sop-java/src/main/java/sop/operation/VerifySignatures.java
+++ /dev/null
@@ -1,46 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-import java.io.ByteArrayInputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.util.List;
-
-import sop.Verification;
-import sop.exception.SOPGPException;
-
-public interface VerifySignatures {
-
-    /**
-     * Provide the signed data (without signatures).
-     *
-     * @param data signed data
-     * @return list of signature verifications
-     * @throws IOException in case of an IO error
-     * @throws SOPGPException.NoSignature when no valid signature is found
-     * @throws SOPGPException.BadData when the data is invalid OpenPGP data
-     */
-    List<Verification> data(InputStream data)
-            throws IOException,
-            SOPGPException.NoSignature,
-            SOPGPException.BadData;
-
-    /**
-     * Provide the signed data (without signatures).
-     *
-     * @param data signed data
-     * @return list of signature verifications
-     * @throws IOException in case of an IO error
-     * @throws SOPGPException.NoSignature when no valid signature is found
-     * @throws SOPGPException.BadData when the data is invalid OpenPGP data
-     */
-    default List<Verification> data(byte[] data)
-            throws IOException,
-            SOPGPException.NoSignature,
-            SOPGPException.BadData {
-        return data(new ByteArrayInputStream(data));
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/operation/VerifySignatures.kt b/sop-java/src/main/kotlin/sop/operation/VerifySignatures.kt
new file mode 100644
index 0000000..b75e4a5
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/VerifySignatures.kt
@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+import java.io.IOException
+import java.io.InputStream
+import sop.Verification
+import sop.exception.SOPGPException.BadData
+import sop.exception.SOPGPException.NoSignature
+
+interface VerifySignatures {
+
+    /**
+     * Provide the signed data (without signatures).
+     *
+     * @param data signed data
+     * @return list of signature verifications
+     * @throws IOException in case of an IO error
+     * @throws NoSignature when no valid signature is found
+     * @throws BadData when the data is invalid OpenPGP data
+     */
+    @Throws(IOException::class, NoSignature::class, BadData::class)
+    fun data(data: InputStream): List<Verification>
+
+    /**
+     * Provide the signed data (without signatures).
+     *
+     * @param data signed data
+     * @return list of signature verifications
+     * @throws IOException in case of an IO error
+     * @throws NoSignature when no valid signature is found
+     * @throws BadData when the data is invalid OpenPGP data
+     */
+    @Throws(IOException::class, NoSignature::class, BadData::class)
+    fun data(data: ByteArray): List<Verification> = data(data.inputStream())
+}

From d0ee9c2066ce0d72cbbd5fb9bcbdf09fbaaa3f17 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:38:34 +0100
Subject: [PATCH 33/46] Kotlin conversion: Version

---
 .../src/main/java/sop/operation/Version.java  | 109 ------------------
 .../main/java/sop/operation/package-info.java |   9 --
 .../src/main/kotlin/sop/operation/Version.kt  | 100 ++++++++++++++++
 3 files changed, 100 insertions(+), 118 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/operation/Version.java
 delete mode 100644 sop-java/src/main/java/sop/operation/package-info.java
 create mode 100644 sop-java/src/main/kotlin/sop/operation/Version.kt

diff --git a/sop-java/src/main/java/sop/operation/Version.java b/sop-java/src/main/java/sop/operation/Version.java
deleted file mode 100644
index b6d66b9..0000000
--- a/sop-java/src/main/java/sop/operation/Version.java
+++ /dev/null
@@ -1,109 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.operation;
-
-public interface Version {
-
-    /**
-     * Return the implementations name.
-     * e.g. "SOP",
-     *
-     * @return implementation name
-     */
-    String getName();
-
-    /**
-     * Return the implementations short version string.
-     * e.g. "1.0"
-     *
-     * @return version string
-     */
-    String getVersion();
-
-    /**
-     * Return version information about the used OpenPGP backend.
-     * e.g. "Bouncycastle 1.70"
-     *
-     * @return backend version string
-     */
-    String getBackendVersion();
-
-    /**
-     * Return an extended version string containing multiple lines of version information.
-     * The first line MUST match the information produced by {@link #getName()} and {@link #getVersion()}, but the rest of the text
-     * has no defined structure.
-     * Example:
-     * <pre>
-     *     "SOP 1.0
-     *     Awesome PGP!
-     *     Using Bouncycastle 1.70
-     *     LibFoo 1.2.2
-     *     See https://pgp.example.org/sop/ for more information"
-     * </pre>
-     *
-     * @return extended version string
-     */
-    String getExtendedVersion();
-
-    /**
-     * Return the revision of the SOP specification that this implementation is implementing, for example,
-     * <pre>draft-dkg-openpgp-stateless-cli-06</pre>.
-     * If the implementation targets a specific draft but the implementer knows the implementation is incomplete,
-     * it should prefix the draft title with a "~" (TILDE, U+007E), for example:
-     * <pre>~draft-dkg-openpgp-stateless-cli-06</pre>.
-     * The implementation MAY emit additional text about its relationship to the targeted draft on the lines following
-     * the versioned title.
-     *
-     * @return implemented SOP spec version
-     */
-    default String getSopSpecVersion() {
-        StringBuilder sb = new StringBuilder();
-        if (isSopSpecImplementationIncomplete()) {
-            sb.append('~');
-        }
-
-        sb.append(getSopSpecRevisionName());
-
-        if (getSopSpecImplementationRemarks() != null) {
-            sb.append('\n')
-                    .append('\n')
-                    .append(getSopSpecImplementationRemarks());
-        }
-
-        return sb.toString();
-    }
-
-    /**
-     * Return the version number of the latest targeted SOP spec revision.
-     *
-     * @return SOP spec revision number
-     */
-    int getSopSpecRevisionNumber();
-
-    /**
-     * Return the name of the latest targeted revision of the SOP spec.
-     *
-     * @return SOP spec revision string
-     */
-    default String getSopSpecRevisionName() {
-        return "draft-dkg-openpgp-stateless-cli-" + String.format("%02d", getSopSpecRevisionNumber());
-    }
-
-    /**
-     * Return <pre>true</pre>, if this implementation of the SOP spec is known to be incomplete or defective.
-     *
-     * @return true if incomplete, false otherwise
-     */
-    boolean isSopSpecImplementationIncomplete();
-
-    /**
-     * Return free-form text containing remarks about the completeness of the SOP implementation.
-     * If there are no remarks, this method returns <pre>null</pre>.
-     *
-     * @return remarks or null
-     */
-    String getSopSpecImplementationRemarks();
-
-}
diff --git a/sop-java/src/main/java/sop/operation/package-info.java b/sop-java/src/main/java/sop/operation/package-info.java
deleted file mode 100644
index dde4d5b..0000000
--- a/sop-java/src/main/java/sop/operation/package-info.java
+++ /dev/null
@@ -1,9 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-/**
- * Stateless OpenPGP Interface for Java.
- * Different cryptographic operations.
- */
-package sop.operation;
diff --git a/sop-java/src/main/kotlin/sop/operation/Version.kt b/sop-java/src/main/kotlin/sop/operation/Version.kt
new file mode 100644
index 0000000..9b3bd8a
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/operation/Version.kt
@@ -0,0 +1,100 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.operation
+
+interface Version {
+
+    /**
+     * Return the implementations name. e.g. `SOP`,
+     *
+     * @return implementation name
+     */
+    fun getName(): String
+
+    /**
+     * Return the implementations short version string. e.g. `1.0`
+     *
+     * @return version string
+     */
+    fun getVersion(): String
+
+    /**
+     * Return version information about the used OpenPGP backend. e.g. `Bouncycastle 1.70`
+     *
+     * @return backend version string
+     */
+    fun getBackendVersion(): String
+
+    /**
+     * Return an extended version string containing multiple lines of version information. The first
+     * line MUST match the information produced by [getName] and [getVersion], but the rest of the
+     * text has no defined structure. Example:
+     * ```
+     * "SOP 1.0
+     * Awesome PGP!
+     * Using Bouncycastle 1.70
+     * LibFoo 1.2.2
+     * See https://pgp.example.org/sop/ for more information"
+     * ```
+     *
+     * @return extended version string
+     */
+    fun getExtendedVersion(): String
+
+    /**
+     * Return the revision of the SOP specification that this implementation is implementing, for
+     * example, `draft-dkg-openpgp-stateless-cli-06`. If the implementation targets a specific draft
+     * but the implementer knows the implementation is incomplete, it should prefix the draft title
+     * with a `~` (TILDE, U+007E), for example: `~draft-dkg-openpgp-stateless-cli-06`. The
+     * implementation MAY emit additional text about its relationship to the targeted draft on the
+     * lines following the versioned title.
+     *
+     * @return implemented SOP spec version
+     */
+    fun getSopSpecVersion(): String {
+        return buildString {
+            if (isSopSpecImplementationIncomplete()) append('~')
+            append(getSopSpecRevisionName())
+            if (getSopSpecImplementationRemarks() != null) {
+                append('\n')
+                append('\n')
+                append(getSopSpecImplementationRemarks())
+            }
+        }
+    }
+
+    /**
+     * Return the version number of the latest targeted SOP spec revision.
+     *
+     * @return SOP spec revision number
+     */
+    fun getSopSpecRevisionNumber(): Int
+
+    /**
+     * Return the name of the latest targeted revision of the SOP spec.
+     *
+     * @return SOP spec revision string
+     */
+    fun getSopSpecRevisionName(): String = buildString {
+        append("draft-dkg-openpgp-stateless-cli-")
+        append(String.format("%02d", getSopSpecRevisionNumber()))
+    }
+
+    /**
+     * Return <pre>true</pre>, if this implementation of the SOP spec is known to be incomplete or
+     * defective.
+     *
+     * @return true if incomplete, false otherwise
+     */
+    fun isSopSpecImplementationIncomplete(): Boolean
+
+    /**
+     * Return free-form text containing remarks about the completeness of the SOP implementation. If
+     * there are no remarks, this method returns <pre>null</pre>.
+     *
+     * @return remarks or null
+     */
+    fun getSopSpecImplementationRemarks(): String?
+}

From 049c18c17ba3907057c65f39dbfa5bf57a0f2960 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:45:56 +0100
Subject: [PATCH 34/46] Fix sop-java-picocli jar task

---
 sop-java-picocli/build.gradle | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sop-java-picocli/build.gradle b/sop-java-picocli/build.gradle
index 664c385..438ef50 100644
--- a/sop-java-picocli/build.gradle
+++ b/sop-java-picocli/build.gradle
@@ -38,6 +38,7 @@ application {
 
 jar {
     dependsOn(":sop-java:jar")
+    duplicatesStrategy(DuplicatesStrategy.EXCLUDE)
 
     manifest {
         attributes 'Main-Class': "$mainClassName"

From 4b9e2c206f18bcec162bb3a82674c151a61239fc Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:46:41 +0100
Subject: [PATCH 35/46] Fix DecryptionResult constructor

---
 sop-java/src/main/kotlin/sop/DecryptionResult.kt | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/sop-java/src/main/kotlin/sop/DecryptionResult.kt b/sop-java/src/main/kotlin/sop/DecryptionResult.kt
index 1ba98bb..b653297 100644
--- a/sop-java/src/main/kotlin/sop/DecryptionResult.kt
+++ b/sop-java/src/main/kotlin/sop/DecryptionResult.kt
@@ -6,11 +6,10 @@ package sop
 
 import sop.util.Optional
 
-data class DecryptionResult
-internal constructor(val sessionKey: Optional<SessionKey>, val verifications: List<Verification>) {
+class DecryptionResult(sessionKey: SessionKey?, val verifications: List<Verification>) {
+    val sessionKey: Optional<SessionKey>
 
-    constructor(
-        sessionKey: SessionKey?,
-        verifications: List<Verification>
-    ) : this(Optional.ofNullable(sessionKey), verifications)
+    init {
+        this.sessionKey = Optional.ofNullable(sessionKey)
+    }
 }

From d5c0d4e390ccd0b0c0171c621eed497d8c897a3b Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:47:14 +0100
Subject: [PATCH 36/46] Kotlin conversion: ArmorLabel

---
 .../src/main/java/sop/enums/ArmorLabel.java   | 19 -------------------
 .../src/main/kotlin/sop/enums/ArmorLabel.kt   | 14 ++++++++++++++
 2 files changed, 14 insertions(+), 19 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/enums/ArmorLabel.java
 create mode 100644 sop-java/src/main/kotlin/sop/enums/ArmorLabel.kt

diff --git a/sop-java/src/main/java/sop/enums/ArmorLabel.java b/sop-java/src/main/java/sop/enums/ArmorLabel.java
deleted file mode 100644
index bb97e84..0000000
--- a/sop-java/src/main/java/sop/enums/ArmorLabel.java
+++ /dev/null
@@ -1,19 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.enums;
-
-public enum ArmorLabel {
-    Auto,
-    Sig,
-    Key,
-    Cert,
-    Message,
-    ;
-
-    @Override
-    public String toString() {
-        return super.toString().toLowerCase();
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/enums/ArmorLabel.kt b/sop-java/src/main/kotlin/sop/enums/ArmorLabel.kt
new file mode 100644
index 0000000..8b4e2cd
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/enums/ArmorLabel.kt
@@ -0,0 +1,14 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.enums
+
+@Deprecated("Use of armor labels is deprecated.")
+enum class ArmorLabel {
+    auto,
+    sig,
+    key,
+    cert,
+    message
+}

From 1c290e0c8f4cae89108adcae5d79334513c49822 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:48:48 +0100
Subject: [PATCH 37/46] Kotlin conversion: EncryptAs

---
 sop-java/src/main/java/sop/enums/EncryptAs.java  | 16 ----------------
 sop-java/src/main/kotlin/sop/enums/EncryptAs.kt  | 10 ++++++++++
 .../testsuite/operation/EncryptDecryptTest.java  |  4 ++--
 3 files changed, 12 insertions(+), 18 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/enums/EncryptAs.java
 create mode 100644 sop-java/src/main/kotlin/sop/enums/EncryptAs.kt

diff --git a/sop-java/src/main/java/sop/enums/EncryptAs.java b/sop-java/src/main/java/sop/enums/EncryptAs.java
deleted file mode 100644
index 7e7d4d1..0000000
--- a/sop-java/src/main/java/sop/enums/EncryptAs.java
+++ /dev/null
@@ -1,16 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.enums;
-
-public enum EncryptAs {
-    Binary,
-    Text,
-    ;
-
-    @Override
-    public String toString() {
-        return super.toString().toLowerCase();
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/enums/EncryptAs.kt b/sop-java/src/main/kotlin/sop/enums/EncryptAs.kt
new file mode 100644
index 0000000..0b6aa8e
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/enums/EncryptAs.kt
@@ -0,0 +1,10 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.enums
+
+enum class EncryptAs {
+    binary,
+    text
+}
diff --git a/sop-java/src/testFixtures/java/sop/testsuite/operation/EncryptDecryptTest.java b/sop-java/src/testFixtures/java/sop/testsuite/operation/EncryptDecryptTest.java
index 0c382dc..9138f64 100644
--- a/sop-java/src/testFixtures/java/sop/testsuite/operation/EncryptDecryptTest.java
+++ b/sop-java/src/testFixtures/java/sop/testsuite/operation/EncryptDecryptTest.java
@@ -142,7 +142,7 @@ public class EncryptDecryptTest extends AbstractSOPTest {
         byte[] ciphertext = sop.encrypt()
                 .withCert(TestData.ALICE_CERT.getBytes(StandardCharsets.UTF_8))
                 .signWith(TestData.ALICE_KEY.getBytes(StandardCharsets.UTF_8))
-                .mode(EncryptAs.Binary)
+                .mode(EncryptAs.binary)
                 .plaintext(message)
                 .getBytes();
 
@@ -173,7 +173,7 @@ public class EncryptDecryptTest extends AbstractSOPTest {
         byte[] ciphertext = sop.encrypt()
                 .withCert(TestData.ALICE_CERT.getBytes(StandardCharsets.UTF_8))
                 .signWith(TestData.ALICE_KEY.getBytes(StandardCharsets.UTF_8))
-                .mode(EncryptAs.Text)
+                .mode(EncryptAs.text)
                 .plaintext(message)
                 .getBytes();
 

From be6be3deac79a922f24285d45b024438b22b3b04 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:50:09 +0100
Subject: [PATCH 38/46] Kotlin conversion: InlineSignAs

---
 .../src/main/java/sop/enums/InlineSignAs.java | 24 -------------------
 .../src/main/kotlin/sop/enums/InlineSignAs.kt | 17 +++++++++++++
 2 files changed, 17 insertions(+), 24 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/enums/InlineSignAs.java
 create mode 100644 sop-java/src/main/kotlin/sop/enums/InlineSignAs.kt

diff --git a/sop-java/src/main/java/sop/enums/InlineSignAs.java b/sop-java/src/main/java/sop/enums/InlineSignAs.java
deleted file mode 100644
index c1097df..0000000
--- a/sop-java/src/main/java/sop/enums/InlineSignAs.java
+++ /dev/null
@@ -1,24 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.enums;
-
-public enum InlineSignAs {
-
-    /**
-     * Signature is made over the binary message.
-     */
-    binary,
-
-    /**
-     * Signature is made over the message in text mode.
-     */
-    text,
-
-    /**
-     * Signature is made using the Cleartext Signature Framework.
-     */
-    clearsigned,
-}
-
diff --git a/sop-java/src/main/kotlin/sop/enums/InlineSignAs.kt b/sop-java/src/main/kotlin/sop/enums/InlineSignAs.kt
new file mode 100644
index 0000000..3440edf
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/enums/InlineSignAs.kt
@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.enums
+
+enum class InlineSignAs {
+
+    /** Signature is made over the binary message. */
+    binary,
+
+    /** Signature is made over the message in text mode. */
+    text,
+
+    /** Signature is made using the Cleartext Signature Framework. */
+    clearsigned
+}

From 30c369d24a10b50b64064963b643e0cd203efec9 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:51:16 +0100
Subject: [PATCH 39/46] Kotlin conversion: SignAs

---
 sop-java/src/main/java/sop/enums/SignAs.java  | 23 -------------------
 sop-java/src/main/kotlin/sop/enums/SignAs.kt  | 12 ++++++++++
 .../DetachedSignDetachedVerifyTest.java       |  2 +-
 3 files changed, 13 insertions(+), 24 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/enums/SignAs.java
 create mode 100644 sop-java/src/main/kotlin/sop/enums/SignAs.kt

diff --git a/sop-java/src/main/java/sop/enums/SignAs.java b/sop-java/src/main/java/sop/enums/SignAs.java
deleted file mode 100644
index 1174098..0000000
--- a/sop-java/src/main/java/sop/enums/SignAs.java
+++ /dev/null
@@ -1,23 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.enums;
-
-public enum SignAs {
-    /**
-     * Signature is made over the binary message.
-     */
-    Binary,
-
-    /**
-     * Signature is made over the message in text mode.
-     */
-    Text,
-    ;
-
-    @Override
-    public String toString() {
-        return super.toString().toLowerCase();
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/enums/SignAs.kt b/sop-java/src/main/kotlin/sop/enums/SignAs.kt
new file mode 100644
index 0000000..832e831
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/enums/SignAs.kt
@@ -0,0 +1,12 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.enums
+
+enum class SignAs {
+    /** Signature is made over the binary message. */
+    binary,
+    /** Signature is made over the message in text mode. */
+    text
+}
diff --git a/sop-java/src/testFixtures/java/sop/testsuite/operation/DetachedSignDetachedVerifyTest.java b/sop-java/src/testFixtures/java/sop/testsuite/operation/DetachedSignDetachedVerifyTest.java
index e715c14..e404599 100644
--- a/sop-java/src/testFixtures/java/sop/testsuite/operation/DetachedSignDetachedVerifyTest.java
+++ b/sop-java/src/testFixtures/java/sop/testsuite/operation/DetachedSignDetachedVerifyTest.java
@@ -62,7 +62,7 @@ public class DetachedSignDetachedVerifyTest extends AbstractSOPTest {
 
         byte[] signature = sop.detachedSign()
                 .key(TestData.ALICE_KEY.getBytes(StandardCharsets.UTF_8))
-                .mode(SignAs.Text)
+                .mode(SignAs.text)
                 .data(message)
                 .toByteArrayAndResult()
                 .getBytes();

From 01f98df80b4f5e6757b887fe99b3c1efc21ceb10 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 14:52:45 +0100
Subject: [PATCH 40/46] Kotlin conversion: SignatureMode

---
 .../main/java/sop/enums/SignatureMode.java    | 25 -------------------
 .../src/main/java/sop/enums/package-info.java |  9 -------
 .../main/kotlin/sop/enums/SignatureMode.kt    | 18 +++++++++++++
 3 files changed, 18 insertions(+), 34 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/enums/SignatureMode.java
 delete mode 100644 sop-java/src/main/java/sop/enums/package-info.java
 create mode 100644 sop-java/src/main/kotlin/sop/enums/SignatureMode.kt

diff --git a/sop-java/src/main/java/sop/enums/SignatureMode.java b/sop-java/src/main/java/sop/enums/SignatureMode.java
deleted file mode 100644
index 71ce7d8..0000000
--- a/sop-java/src/main/java/sop/enums/SignatureMode.java
+++ /dev/null
@@ -1,25 +0,0 @@
-// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.enums;
-
-/**
- * Enum referencing relevant signature types.
- *
- * @see <a href="https://www.rfc-editor.org/rfc/rfc4880#section-5.2.1">
- *     RFC4880 §5.2.1 - Signature Types</a>
- */
-public enum SignatureMode {
-    /**
-     * Signature of a binary document (<pre>0x00</pre>).
-     */
-    binary,
-
-    /**
-     * Signature of a canonical text document (<pre>0x01</pre>).
-     */
-    text
-
-    // Other Signature Types are irrelevant.
-}
diff --git a/sop-java/src/main/java/sop/enums/package-info.java b/sop-java/src/main/java/sop/enums/package-info.java
deleted file mode 100644
index 67148d3..0000000
--- a/sop-java/src/main/java/sop/enums/package-info.java
+++ /dev/null
@@ -1,9 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-/**
- * Stateless OpenPGP Interface for Java.
- * Enumerations.
- */
-package sop.enums;
diff --git a/sop-java/src/main/kotlin/sop/enums/SignatureMode.kt b/sop-java/src/main/kotlin/sop/enums/SignatureMode.kt
new file mode 100644
index 0000000..7213195
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/enums/SignatureMode.kt
@@ -0,0 +1,18 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.enums
+
+/**
+ * Enum referencing relevant signature types.
+ *
+ * @see <a href="https://www.rfc-editor.org/rfc/rfc4880#section-5.2.1"> RFC4880 §5.2.1 - Signature
+ *   Types</a>
+ */
+enum class SignatureMode {
+    /** Signature of a binary document (type `0x00`). */
+    binary,
+    /** Signature of a canonical text document (type `0x01`). */
+    text
+}

From b7007cc0070659c58e0e9cad520acd58b6b07342 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 15:00:21 +0100
Subject: [PATCH 41/46] Kotlin conversion: HexUtil

---
 sop-java/src/main/java/sop/util/HexUtil.java | 47 --------------------
 sop-java/src/main/kotlin/sop/util/HexUtil.kt | 38 ++++++++++++++++
 2 files changed, 38 insertions(+), 47 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/util/HexUtil.java
 create mode 100644 sop-java/src/main/kotlin/sop/util/HexUtil.kt

diff --git a/sop-java/src/main/java/sop/util/HexUtil.java b/sop-java/src/main/java/sop/util/HexUtil.java
deleted file mode 100644
index 9b88f53..0000000
--- a/sop-java/src/main/java/sop/util/HexUtil.java
+++ /dev/null
@@ -1,47 +0,0 @@
-// Copyright 2021 Paul Schaub, @maybeWeCouldStealAVan, @Dave L.
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.util;
-
-public class HexUtil {
-
-    private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();
-
-    /**
-     * Encode a byte array to a hex string.
-     *
-     * @see <a href="https://stackoverflow.com/a/9855338">
-     *     How to convert a byte array to a hex string in Java?</a>
-     * @param bytes bytes
-     * @return hex encoding
-     */
-    public static String bytesToHex(byte[] bytes) {
-        char[] hexChars = new char[bytes.length * 2];
-        for (int j = 0; j < bytes.length; j++) {
-            int v = bytes[j] & 0xFF;
-            hexChars[j * 2] = HEX_ARRAY[v >>> 4];
-            hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
-        }
-        return new String(hexChars);
-    }
-
-    /**
-     * Decode a hex string into a byte array.
-     *
-     * @see <a href="https://stackoverflow.com/a/140861">
-     *     Convert a string representation of a hex dump to a byte array using Java?</a>
-     * @param s hex string
-     * @return decoded byte array
-     */
-    public static byte[] hexToBytes(String s) {
-        int len = s.length();
-        byte[] data = new byte[len / 2];
-        for (int i = 0; i < len; i += 2) {
-            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
-                    + Character.digit(s.charAt(i + 1), 16));
-        }
-        return data;
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/util/HexUtil.kt b/sop-java/src/main/kotlin/sop/util/HexUtil.kt
new file mode 100644
index 0000000..f372137
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/util/HexUtil.kt
@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.util
+
+class HexUtil {
+
+    companion object {
+        /**
+         * Encode a byte array to a hex string.
+         *
+         * @param bytes bytes
+         * @return hex encoding
+         * @see
+         *   [Convert Byte Arrays to Hex Strings in Kotlin](https://www.baeldung.com/kotlin/byte-arrays-to-hex-strings)
+         */
+        @JvmStatic fun bytesToHex(bytes: ByteArray): String = bytes.toHex()
+
+        /**
+         * Decode a hex string into a byte array.
+         *
+         * @param s hex string
+         * @return decoded byte array
+         * @see
+         *   [Kotlin convert hex string to ByteArray](https://stackoverflow.com/a/66614516/11150851)
+         */
+        @JvmStatic fun hexToBytes(s: String): ByteArray = s.decodeHex()
+    }
+}
+
+fun String.decodeHex(): ByteArray {
+    check(length % 2 == 0) { "Hex encoding must have even number of digits." }
+
+    return chunked(2).map { it.toInt(16).toByte() }.toByteArray()
+}
+
+fun ByteArray.toHex(): String = joinToString(separator = "") { eachByte -> "%02X".format(eachByte) }

From 05886228df497c18ce94ffd756fc2075e48b0a95 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 15:07:13 +0100
Subject: [PATCH 42/46] Kotlin conversion: ProxyOutputStream

---
 .../main/java/sop/util/ProxyOutputStream.java | 80 -------------------
 .../main/kotlin/sop/util/ProxyOutputStream.kt | 75 +++++++++++++++++
 2 files changed, 75 insertions(+), 80 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/util/ProxyOutputStream.java
 create mode 100644 sop-java/src/main/kotlin/sop/util/ProxyOutputStream.kt

diff --git a/sop-java/src/main/java/sop/util/ProxyOutputStream.java b/sop-java/src/main/java/sop/util/ProxyOutputStream.java
deleted file mode 100644
index ed24fc2..0000000
--- a/sop-java/src/main/java/sop/util/ProxyOutputStream.java
+++ /dev/null
@@ -1,80 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.util;
-
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.OutputStream;
-
-/**
- * {@link OutputStream} that buffers data being written into it, until its underlying output stream is being replaced.
- * At that point, first all the buffered data is being written to the underlying stream, followed by any successive
- * data that may get written to the {@link ProxyOutputStream}.
- * <p>
- * This class is useful if we need to provide an {@link OutputStream} at one point in time when the final
- * target output stream is not yet known.
- */
-public class ProxyOutputStream extends OutputStream {
-
-    private final ByteArrayOutputStream buffer;
-    private OutputStream swapped;
-
-    public ProxyOutputStream() {
-        this.buffer = new ByteArrayOutputStream();
-    }
-
-    public synchronized void replaceOutputStream(OutputStream underlying) throws IOException {
-        if (underlying == null) {
-            throw new NullPointerException("Underlying OutputStream cannot be null.");
-        }
-        this.swapped = underlying;
-
-        byte[] bufferBytes = buffer.toByteArray();
-        swapped.write(bufferBytes);
-    }
-
-    @Override
-    public synchronized void write(byte[] b) throws IOException {
-        if (swapped == null) {
-            buffer.write(b);
-        } else {
-            swapped.write(b);
-        }
-    }
-
-    @Override
-    public synchronized void write(byte[] b, int off, int len) throws IOException {
-        if (swapped == null) {
-            buffer.write(b, off, len);
-        } else {
-            swapped.write(b, off, len);
-        }
-    }
-
-    @Override
-    public synchronized void flush() throws IOException {
-        buffer.flush();
-        if (swapped != null) {
-            swapped.flush();
-        }
-    }
-
-    @Override
-    public synchronized void close() throws IOException {
-        buffer.close();
-        if (swapped != null) {
-            swapped.close();
-        }
-    }
-
-    @Override
-    public synchronized void write(int i) throws IOException {
-        if (swapped == null) {
-            buffer.write(i);
-        } else {
-            swapped.write(i);
-        }
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/util/ProxyOutputStream.kt b/sop-java/src/main/kotlin/sop/util/ProxyOutputStream.kt
new file mode 100644
index 0000000..142f7b3
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/util/ProxyOutputStream.kt
@@ -0,0 +1,75 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.util
+
+import java.io.ByteArrayOutputStream
+import java.io.IOException
+import java.io.OutputStream
+
+/**
+ * [OutputStream] that buffers data being written into it, until its underlying output stream is
+ * being replaced. At that point, first all the buffered data is being written to the underlying
+ * stream, followed by any successive data that may get written to the [ProxyOutputStream]. This
+ * class is useful if we need to provide an [OutputStream] at one point in time when the final
+ * target output stream is not yet known.
+ */
+class ProxyOutputStream {
+    private val buffer = ByteArrayOutputStream()
+    private var swapped: OutputStream? = null
+
+    @Synchronized
+    fun replaceOutputStream(underlying: OutputStream) {
+        this.swapped = underlying
+        swapped!!.write(buffer.toByteArray())
+    }
+
+    @Synchronized
+    @Throws(IOException::class)
+    fun write(b: ByteArray) {
+        if (swapped == null) {
+            buffer.write(b)
+        } else {
+            swapped!!.write(b)
+        }
+    }
+
+    @Synchronized
+    @Throws(IOException::class)
+    fun write(b: ByteArray, off: Int, len: Int) {
+        if (swapped == null) {
+            buffer.write(b, off, len)
+        } else {
+            swapped!!.write(b, off, len)
+        }
+    }
+
+    @Synchronized
+    @Throws(IOException::class)
+    fun flush() {
+        buffer.flush()
+        if (swapped != null) {
+            swapped!!.flush()
+        }
+    }
+
+    @Synchronized
+    @Throws(IOException::class)
+    fun close() {
+        buffer.close()
+        if (swapped != null) {
+            swapped!!.close()
+        }
+    }
+
+    @Synchronized
+    @Throws(IOException::class)
+    fun write(i: Int) {
+        if (swapped == null) {
+            buffer.write(i)
+        } else {
+            swapped!!.write(i)
+        }
+    }
+}

From 25a33611fdab6eba7cb3625677d37ccd5c16fd7d Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 15:10:46 +0100
Subject: [PATCH 43/46] Kotlin conversion: UTCUtil

---
 sop-java/src/main/java/sop/util/UTCUtil.java | 65 --------------------
 sop-java/src/main/kotlin/sop/util/UTCUtil.kt | 62 +++++++++++++++++++
 2 files changed, 62 insertions(+), 65 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/util/UTCUtil.java
 create mode 100644 sop-java/src/main/kotlin/sop/util/UTCUtil.kt

diff --git a/sop-java/src/main/java/sop/util/UTCUtil.java b/sop-java/src/main/java/sop/util/UTCUtil.java
deleted file mode 100644
index 96a6b9c..0000000
--- a/sop-java/src/main/java/sop/util/UTCUtil.java
+++ /dev/null
@@ -1,65 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.util;
-
-import javax.annotation.Nonnull;
-import java.text.ParseException;
-import java.text.SimpleDateFormat;
-import java.util.Date;
-import java.util.TimeZone;
-
-/**
- * Utility class to parse and format dates as ISO-8601 UTC timestamps.
- */
-public class UTCUtil {
-
-    public static final SimpleDateFormat UTC_FORMATTER = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
-    public static final SimpleDateFormat[] UTC_PARSERS = new SimpleDateFormat[] {
-            UTC_FORMATTER,
-            new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssX"),
-            new SimpleDateFormat("yyyyMMdd'T'HHmmss'Z'"),
-            new SimpleDateFormat("yyyy-MM-dd'T'HH:mm'Z'")
-    };
-
-    static {
-        for (SimpleDateFormat f : UTC_PARSERS) {
-            f.setTimeZone(TimeZone.getTimeZone("UTC"));
-        }
-    }
-    /**
-     * Parse an ISO-8601 UTC timestamp from a string.
-     *
-     * @param dateString string
-     * @return date
-     * @throws ParseException if the date string is malformed and cannot be parsed
-     */
-    @Nonnull
-    public static Date parseUTCDate(String dateString) throws ParseException {
-        ParseException exception = null;
-        for (SimpleDateFormat parser : UTC_PARSERS) {
-            try {
-                return parser.parse(dateString);
-            } catch (ParseException e) {
-                // Store first exception (that of UTC_FORMATTER) to throw if we fail to parse the date
-                if (exception == null) {
-                    exception = e;
-                }
-                // Try next parser
-            }
-        }
-        // No parser worked, so we throw the store exception
-        throw exception;
-    }
-
-    /**
-     * Format a date as ISO-8601 UTC timestamp.
-     *
-     * @param date date
-     * @return timestamp string
-     */
-    public static String formatUTCDate(Date date) {
-        return UTC_FORMATTER.format(date);
-    }
-}
diff --git a/sop-java/src/main/kotlin/sop/util/UTCUtil.kt b/sop-java/src/main/kotlin/sop/util/UTCUtil.kt
new file mode 100644
index 0000000..8924f25
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/util/UTCUtil.kt
@@ -0,0 +1,62 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.util
+
+import java.text.ParseException
+import java.text.SimpleDateFormat
+import java.util.*
+
+class UTCUtil {
+
+    companion object {
+
+        @JvmStatic val UTC_FORMATTER = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'")
+        @JvmStatic
+        val UTC_PARSERS =
+            arrayOf(
+                    UTC_FORMATTER,
+                    SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssX"),
+                    SimpleDateFormat("yyyyMMdd'T'HHmmss'Z'"),
+                    SimpleDateFormat("yyyy-MM-dd'T'HH:mm'Z'"))
+                .onEach { fmt -> fmt.timeZone = TimeZone.getTimeZone("UTC") }
+
+        /**
+         * Parse an ISO-8601 UTC timestamp from a string.
+         *
+         * @param dateString string
+         * @return date
+         * @throws ParseException if the date string is malformed and cannot be parsed
+         */
+        @JvmStatic
+        @Throws(ParseException::class)
+        fun parseUTCDate(dateString: String): Date {
+            var exception: ParseException? = null
+            for (parser in UTC_PARSERS) {
+                try {
+                    return parser.parse(dateString)
+                } catch (e: ParseException) {
+                    // Store first exception (that of UTC_FORMATTER) to throw if we fail to parse
+                    // the date
+                    if (exception == null) {
+                        exception = e
+                    }
+                    // Try next parser
+                }
+            }
+            throw exception!!
+        }
+
+        /**
+         * Format a date as ISO-8601 UTC timestamp.
+         *
+         * @param date date
+         * @return timestamp string
+         */
+        @JvmStatic
+        fun formatUTCDate(date: Date): String {
+            return UTC_FORMATTER.format(date)
+        }
+    }
+}

From e1a6ffd07a7e081e207f84d105344013f9535b17 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 15:18:39 +0100
Subject: [PATCH 44/46] Use @JvmField annotation

---
 sop-java/src/main/kotlin/sop/util/UTCUtil.kt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sop-java/src/main/kotlin/sop/util/UTCUtil.kt b/sop-java/src/main/kotlin/sop/util/UTCUtil.kt
index 8924f25..4ae13bc 100644
--- a/sop-java/src/main/kotlin/sop/util/UTCUtil.kt
+++ b/sop-java/src/main/kotlin/sop/util/UTCUtil.kt
@@ -12,8 +12,8 @@ class UTCUtil {
 
     companion object {
 
-        @JvmStatic val UTC_FORMATTER = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'")
-        @JvmStatic
+        @JvmField val UTC_FORMATTER = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'")
+        @JvmField
         val UTC_PARSERS =
             arrayOf(
                     UTC_FORMATTER,

From 94b428ef62cc9735fad20cca4560eb14af6a2b41 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 15:18:48 +0100
Subject: [PATCH 45/46] Kotlin conversion: UTF8Util

---
 sop-java/src/main/java/sop/util/UTF8Util.java | 37 -------------------
 .../src/main/java/sop/util/package-info.java  |  8 ----
 sop-java/src/main/kotlin/sop/util/UTF8Util.kt | 37 +++++++++++++++++++
 3 files changed, 37 insertions(+), 45 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/util/UTF8Util.java
 delete mode 100644 sop-java/src/main/java/sop/util/package-info.java
 create mode 100644 sop-java/src/main/kotlin/sop/util/UTF8Util.kt

diff --git a/sop-java/src/main/java/sop/util/UTF8Util.java b/sop-java/src/main/java/sop/util/UTF8Util.java
deleted file mode 100644
index 1b4941b..0000000
--- a/sop-java/src/main/java/sop/util/UTF8Util.java
+++ /dev/null
@@ -1,37 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.util;
-
-import java.nio.ByteBuffer;
-import java.nio.CharBuffer;
-import java.nio.charset.CharacterCodingException;
-import java.nio.charset.Charset;
-import java.nio.charset.CharsetDecoder;
-import java.nio.charset.CodingErrorAction;
-
-public class UTF8Util {
-
-    public static final Charset UTF8 = Charset.forName("UTF8");
-    private static final CharsetDecoder UTF8Decoder = UTF8
-            .newDecoder()
-            .onUnmappableCharacter(CodingErrorAction.REPORT)
-            .onMalformedInput(CodingErrorAction.REPORT);
-
-    /**
-     * Detect non-valid UTF8 data.
-     *
-     * @see <a href="https://stackoverflow.com/a/1471193">ante on StackOverflow</a>
-     * @param data utf-8 encoded bytes
-     *
-     * @return decoded string
-     * @throws CharacterCodingException if the input data does not resemble UTF8
-     */
-    public static String decodeUTF8(byte[] data)
-            throws CharacterCodingException {
-        ByteBuffer byteBuffer = ByteBuffer.wrap(data);
-        CharBuffer charBuffer = UTF8Decoder.decode(byteBuffer);
-        return charBuffer.toString();
-    }
-}
diff --git a/sop-java/src/main/java/sop/util/package-info.java b/sop-java/src/main/java/sop/util/package-info.java
deleted file mode 100644
index 3dd9fc1..0000000
--- a/sop-java/src/main/java/sop/util/package-info.java
+++ /dev/null
@@ -1,8 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-/**
- * Utility classes.
- */
-package sop.util;
diff --git a/sop-java/src/main/kotlin/sop/util/UTF8Util.kt b/sop-java/src/main/kotlin/sop/util/UTF8Util.kt
new file mode 100644
index 0000000..770f32c
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/util/UTF8Util.kt
@@ -0,0 +1,37 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.util
+
+import java.nio.ByteBuffer
+import java.nio.charset.Charset
+import java.nio.charset.CodingErrorAction
+
+class UTF8Util {
+    companion object {
+        @JvmField val UTF8: Charset = Charset.forName("UTF8")
+
+        @JvmStatic
+        private val UTF8Decoder =
+            UTF8.newDecoder()
+                .onUnmappableCharacter(CodingErrorAction.REPORT)
+                .onMalformedInput(CodingErrorAction.REPORT)
+
+        /**
+         * Detect non-valid UTF8 data.
+         *
+         * @param data utf-8 encoded bytes
+         * @return decoded string
+         * @throws CharacterCodingException if the input data does not resemble UTF8
+         * @see [ante on StackOverflow](https://stackoverflow.com/a/1471193)
+         */
+        @JvmStatic
+        @Throws(CharacterCodingException::class)
+        fun decodeUTF8(data: ByteArray): String {
+            val byteBuffer = ByteBuffer.wrap(data)
+            val charBuffer = UTF8Decoder.decode(byteBuffer)
+            return charBuffer.toString()
+        }
+    }
+}

From 7824ee92c536f990de01c63d07c2dbfd68f4f579 Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Tue, 31 Oct 2023 15:27:47 +0100
Subject: [PATCH 46/46] Kotlin conversion: SOPGPException

---
 .../java/sop/exception/SOPGPException.java    | 473 ------------------
 .../main/java/sop/exception/package-info.java |   9 -
 sop-java/src/main/java/sop/package-info.java  |   8 -
 .../kotlin/sop/exception/SOPGPException.kt    | 308 ++++++++++++
 4 files changed, 308 insertions(+), 490 deletions(-)
 delete mode 100644 sop-java/src/main/java/sop/exception/SOPGPException.java
 delete mode 100644 sop-java/src/main/java/sop/exception/package-info.java
 delete mode 100644 sop-java/src/main/java/sop/package-info.java
 create mode 100644 sop-java/src/main/kotlin/sop/exception/SOPGPException.kt

diff --git a/sop-java/src/main/java/sop/exception/SOPGPException.java b/sop-java/src/main/java/sop/exception/SOPGPException.java
deleted file mode 100644
index 1d13065..0000000
--- a/sop-java/src/main/java/sop/exception/SOPGPException.java
+++ /dev/null
@@ -1,473 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package sop.exception;
-
-public abstract class SOPGPException extends RuntimeException {
-
-    public SOPGPException() {
-        super();
-    }
-
-    public SOPGPException(String message) {
-        super(message);
-    }
-
-    public SOPGPException(Throwable e) {
-        super(e);
-    }
-
-    public SOPGPException(String message, Throwable cause) {
-        super(message, cause);
-    }
-
-    public abstract int getExitCode();
-
-    /**
-     * No acceptable signatures found (sop verify, inline-verify).
-     */
-    public static class NoSignature extends SOPGPException {
-
-        public static final int EXIT_CODE = 3;
-
-        public NoSignature() {
-            this("No verifiable signature found.");
-        }
-
-        public NoSignature(String message) {
-            super(message);
-        }
-
-        public NoSignature(String errorMsg, NoSignature e) {
-            super(errorMsg, e);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Asymmetric algorithm unsupported (sop encrypt, sign, inline-sign).
-     */
-    public static class UnsupportedAsymmetricAlgo extends SOPGPException {
-
-        public static final int EXIT_CODE = 13;
-
-        public UnsupportedAsymmetricAlgo(String message, Throwable e) {
-            super(message, e);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Certificate not encryption capable (e,g, expired, revoked, unacceptable usage).
-     */
-    public static class CertCannotEncrypt extends SOPGPException {
-        public static final int EXIT_CODE = 17;
-
-        public CertCannotEncrypt(String message, Throwable cause) {
-            super(message, cause);
-        }
-
-        public CertCannotEncrypt(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Missing required argument.
-     */
-    public static class MissingArg extends SOPGPException {
-
-        public static final int EXIT_CODE = 19;
-
-        public MissingArg() {
-
-        }
-
-        public MissingArg(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Incomplete verification instructions (sop decrypt).
-     */
-    public static class IncompleteVerification extends SOPGPException {
-
-        public static final int EXIT_CODE = 23;
-
-        public IncompleteVerification(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Unable to decrypt (sop decrypt).
-     */
-    public static class CannotDecrypt extends SOPGPException {
-
-        public static final int EXIT_CODE = 29;
-
-        public CannotDecrypt() {
-
-        }
-
-        public CannotDecrypt(String errorMsg, Throwable e) {
-            super(errorMsg, e);
-        }
-
-        public CannotDecrypt(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Non-UTF-8 or otherwise unreliable password (sop encrypt).
-     */
-    public static class PasswordNotHumanReadable extends SOPGPException {
-
-        public static final int EXIT_CODE = 31;
-
-        public PasswordNotHumanReadable() {
-            super();
-        }
-
-        public PasswordNotHumanReadable(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Unsupported option.
-     */
-    public static class UnsupportedOption extends SOPGPException {
-
-        public static final int EXIT_CODE = 37;
-
-        public UnsupportedOption(String message) {
-            super(message);
-        }
-
-        public UnsupportedOption(String message, Throwable cause) {
-            super(message, cause);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Invalid data type (no secret key where KEYS expected, etc.).
-     */
-    public static class BadData extends SOPGPException {
-
-        public static final int EXIT_CODE = 41;
-
-        public BadData(String message) {
-            super(message);
-        }
-
-        public BadData(Throwable throwable) {
-            super(throwable);
-        }
-
-        public BadData(String message, Throwable throwable) {
-            super(message, throwable);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Non-Text input where text expected.
-     */
-    public static class ExpectedText extends SOPGPException {
-
-        public static final int EXIT_CODE = 53;
-
-        public ExpectedText() {
-            super();
-        }
-
-        public ExpectedText(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Output file already exists.
-     */
-    public static class OutputExists extends SOPGPException {
-
-        public static final int EXIT_CODE = 59;
-
-        public OutputExists(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Input file does not exist.
-     */
-    public static class MissingInput extends SOPGPException {
-
-        public static final int EXIT_CODE = 61;
-
-        public MissingInput(String message, Throwable cause) {
-            super(message, cause);
-        }
-
-        public MissingInput(String errorMsg) {
-            super(errorMsg);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * A KEYS input is protected (locked) with a password and sop failed to unlock it.
-     */
-    public static class KeyIsProtected extends SOPGPException {
-
-        public static final int EXIT_CODE = 67;
-
-        public KeyIsProtected() {
-            super();
-        }
-
-        public KeyIsProtected(String message) {
-            super(message);
-        }
-
-        public KeyIsProtected(String message, Throwable cause) {
-            super(message, cause);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Unsupported subcommand.
-     */
-    public static class UnsupportedSubcommand extends SOPGPException {
-
-        public static final int EXIT_CODE = 69;
-
-        public UnsupportedSubcommand(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * An indirect parameter is a special designator (it starts with @), but sop does not know how to handle the prefix.
-     */
-    public static class UnsupportedSpecialPrefix extends SOPGPException {
-
-        public static final int EXIT_CODE = 71;
-
-        public UnsupportedSpecialPrefix(String errorMsg) {
-            super(errorMsg);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Exception that gets thrown if a special designator (starting with @) is given, but the filesystem contains
-     * a file matching the designator.
-     * <p>
-     * E.g. <pre>@ENV:FOO</pre> is given, but <pre>./@ENV:FOO</pre> exists on the filesystem.
-     */
-    public static class AmbiguousInput extends SOPGPException {
-
-        public static final int EXIT_CODE = 73;
-
-        public AmbiguousInput(String message) {
-            super(message);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * Key not signature-capable (e.g. expired, revoked, unacceptable usage flags).
-     */
-    public static class KeyCannotSign extends SOPGPException {
-
-        public static final int EXIT_CODE = 79;
-
-        public KeyCannotSign() {
-            super();
-        }
-
-        public KeyCannotSign(String message) {
-            super(message);
-        }
-
-        public KeyCannotSign(String s, Throwable throwable) {
-            super(s, throwable);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * User provided incompatible options (e.g. "--as=clearsigned --no-armor").
-     */
-    public static class IncompatibleOptions extends SOPGPException {
-
-        public static final int EXIT_CODE = 83;
-
-        public IncompatibleOptions() {
-            super();
-        }
-
-        public IncompatibleOptions(String errorMsg) {
-            super(errorMsg);
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-
-    /**
-     * The user provided a subcommand with an unsupported profile ("--profile=XYZ"),
-     * or the user tried to list profiles of a subcommand that does not support profiles at all.
-     */
-    public static class UnsupportedProfile extends SOPGPException {
-
-        public static final int EXIT_CODE = 89;
-
-        private final String subcommand;
-        private final String profile;
-
-        /**
-         * Create an exception signalling a subcommand that does not support any profiles.
-         *
-         * @param subcommand subcommand
-         */
-        public UnsupportedProfile(String subcommand) {
-            super("Subcommand '" + subcommand + "' does not support any profiles.");
-            this.subcommand = subcommand;
-            this.profile = null;
-        }
-
-        /**
-         * Create an exception signalling a subcommand does not support a specific profile.
-         *
-         * @param subcommand subcommand
-         * @param profile unsupported profile
-         */
-        public UnsupportedProfile(String subcommand, String profile) {
-            super("Subcommand '" + subcommand + "' does not support profile '" + profile + "'.");
-            this.subcommand = subcommand;
-            this.profile = profile;
-        }
-
-        /**
-         * Wrap an exception into another instance with a possibly translated error message.
-         *
-         * @param errorMsg error message
-         * @param e exception
-         */
-        public UnsupportedProfile(String errorMsg, UnsupportedProfile e) {
-            super(errorMsg, e);
-            this.subcommand = e.getSubcommand();
-            this.profile = e.getProfile();
-        }
-
-        /**
-         * Return the subcommand name.
-         *
-         * @return subcommand
-         */
-        public String getSubcommand() {
-            return subcommand;
-        }
-
-        /**
-         * Return the profile name.
-         * May return <pre>null</pre>.
-         *
-         * @return profile name
-         */
-        public String getProfile() {
-            return profile;
-        }
-
-        @Override
-        public int getExitCode() {
-            return EXIT_CODE;
-        }
-    }
-}
diff --git a/sop-java/src/main/java/sop/exception/package-info.java b/sop-java/src/main/java/sop/exception/package-info.java
deleted file mode 100644
index 4abc562..0000000
--- a/sop-java/src/main/java/sop/exception/package-info.java
+++ /dev/null
@@ -1,9 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-/**
- * Stateless OpenPGP Interface for Java.
- * Exception classes.
- */
-package sop.exception;
diff --git a/sop-java/src/main/java/sop/package-info.java b/sop-java/src/main/java/sop/package-info.java
deleted file mode 100644
index 5ad4f52..0000000
--- a/sop-java/src/main/java/sop/package-info.java
+++ /dev/null
@@ -1,8 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-/**
- * Stateless OpenPGP Interface for Java.
- */
-package sop;
diff --git a/sop-java/src/main/kotlin/sop/exception/SOPGPException.kt b/sop-java/src/main/kotlin/sop/exception/SOPGPException.kt
new file mode 100644
index 0000000..2473258
--- /dev/null
+++ b/sop-java/src/main/kotlin/sop/exception/SOPGPException.kt
@@ -0,0 +1,308 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package sop.exception
+
+abstract class SOPGPException : RuntimeException {
+
+    constructor() : super()
+
+    constructor(message: String) : super(message)
+
+    constructor(cause: Throwable) : super(cause)
+
+    constructor(message: String, cause: Throwable) : super(message, cause)
+
+    abstract fun getExitCode(): Int
+
+    /** No acceptable signatures found (sop verify, inline-verify). */
+    class NoSignature : SOPGPException {
+        @JvmOverloads
+        constructor(message: String = "No verifiable signature found.") : super(message)
+
+        constructor(errorMsg: String, e: NoSignature) : super(errorMsg, e)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 3
+        }
+    }
+
+    /** Asymmetric algorithm unsupported (sop encrypt, sign, inline-sign). */
+    class UnsupportedAsymmetricAlgo(message: String, e: Throwable) : SOPGPException(message, e) {
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 13
+        }
+    }
+
+    /** Certificate not encryption capable (e,g, expired, revoked, unacceptable usage). */
+    class CertCannotEncrypt : SOPGPException {
+        constructor(message: String, cause: Throwable) : super(message, cause)
+
+        constructor(message: String) : super(message)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 17
+        }
+    }
+
+    /** Missing required argument. */
+    class MissingArg : SOPGPException {
+        constructor()
+
+        constructor(message: String) : super(message)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 19
+        }
+    }
+
+    /** Incomplete verification instructions (sop decrypt). */
+    class IncompleteVerification(message: String) : SOPGPException(message) {
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 23
+        }
+    }
+
+    /** Unable to decrypt (sop decrypt). */
+    class CannotDecrypt : SOPGPException {
+        constructor()
+
+        constructor(errorMsg: String, e: Throwable) : super(errorMsg, e)
+
+        constructor(message: String) : super(message)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 29
+        }
+    }
+
+    /** Non-UTF-8 or otherwise unreliable password (sop encrypt). */
+    class PasswordNotHumanReadable : SOPGPException {
+        constructor() : super()
+
+        constructor(message: String) : super(message)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 31
+        }
+    }
+
+    /** Unsupported option. */
+    class UnsupportedOption : SOPGPException {
+        constructor(message: String) : super(message)
+
+        constructor(message: String, cause: Throwable) : super(message, cause)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 37
+        }
+    }
+
+    /** Invalid data type (no secret key where KEYS expected, etc.). */
+    class BadData : SOPGPException {
+        constructor(message: String) : super(message)
+
+        constructor(throwable: Throwable) : super(throwable)
+
+        constructor(message: String, throwable: Throwable) : super(message, throwable)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 41
+        }
+    }
+
+    /** Non-Text input where text expected. */
+    class ExpectedText : SOPGPException {
+        constructor() : super()
+
+        constructor(message: String) : super(message)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 53
+        }
+    }
+
+    /** Output file already exists. */
+    class OutputExists(message: String) : SOPGPException(message) {
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 59
+        }
+    }
+
+    /** Input file does not exist. */
+    class MissingInput : SOPGPException {
+        constructor(message: String, cause: Throwable) : super(message, cause)
+
+        constructor(errorMsg: String) : super(errorMsg)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 61
+        }
+    }
+
+    /** A KEYS input is protected (locked) with a password and sop failed to unlock it. */
+    class KeyIsProtected : SOPGPException {
+        constructor() : super()
+
+        constructor(message: String) : super(message)
+
+        constructor(message: String, cause: Throwable) : super(message, cause)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 67
+        }
+    }
+
+    /** Unsupported subcommand. */
+    class UnsupportedSubcommand(message: String) : SOPGPException(message) {
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 69
+        }
+    }
+
+    /**
+     * An indirect parameter is a special designator (it starts with @), but sop does not know how
+     * to handle the prefix.
+     */
+    class UnsupportedSpecialPrefix(errorMsg: String) : SOPGPException(errorMsg) {
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 71
+        }
+    }
+
+    /**
+     * Exception that gets thrown if a special designator (starting with @) is given, but the
+     * filesystem contains a file matching the designator.
+     *
+     * E.g. <pre>@ENV:FOO</pre> is given, but <pre>./@ENV:FOO</pre> exists on the filesystem.
+     */
+    class AmbiguousInput(message: String) : SOPGPException(message) {
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 73
+        }
+    }
+
+    /** Key not signature-capable (e.g. expired, revoked, unacceptable usage flags). */
+    class KeyCannotSign : SOPGPException {
+        constructor() : super()
+
+        constructor(message: String) : super(message)
+
+        constructor(s: String, throwable: Throwable) : super(s, throwable)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 79
+        }
+    }
+
+    /** User provided incompatible options (e.g. "--as=clearsigned --no-armor"). */
+    class IncompatibleOptions : SOPGPException {
+        constructor() : super()
+
+        constructor(errorMsg: String) : super(errorMsg)
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 83
+        }
+    }
+
+    /**
+     * The user provided a subcommand with an unsupported profile ("--profile=XYZ"), or the user
+     * tried to list profiles of a subcommand that does not support profiles at all.
+     */
+    class UnsupportedProfile : SOPGPException {
+        /**
+         * Return the subcommand name.
+         *
+         * @return subcommand
+         */
+        val subcommand: String
+
+        /**
+         * Return the profile name. May return `null`.
+         *
+         * @return profile name
+         */
+        val profile: String?
+
+        /**
+         * Create an exception signalling a subcommand that does not support any profiles.
+         *
+         * @param subcommand subcommand
+         */
+        constructor(
+            subcommand: String
+        ) : super("Subcommand '$subcommand' does not support any profiles.") {
+            this.subcommand = subcommand
+            profile = null
+        }
+
+        /**
+         * Create an exception signalling a subcommand does not support a specific profile.
+         *
+         * @param subcommand subcommand
+         * @param profile unsupported profile
+         */
+        constructor(
+            subcommand: String,
+            profile: String
+        ) : super("Subcommand '$subcommand' does not support profile '$profile'.") {
+            this.subcommand = subcommand
+            this.profile = profile
+        }
+
+        /**
+         * Wrap an exception into another instance with a possibly translated error message.
+         *
+         * @param errorMsg error message
+         * @param e exception
+         */
+        constructor(errorMsg: String, e: UnsupportedProfile) : super(errorMsg, e) {
+            subcommand = e.subcommand
+            profile = e.profile
+        }
+
+        override fun getExitCode(): Int = EXIT_CODE
+
+        companion object {
+            const val EXIT_CODE = 89
+        }
+    }
+}