Add support for OpenPGP v5 fingerprints.

Obviously we need support for key.getFingerprint() in BC, but once
that is there, this should magically start working.

pgpainless-core/src/main/java/org/pgpainless/key/OpenPgpFingerprint.java

@@ -33,6 +33,9 @@ public abstract class OpenPgpFingerprint implements CharSequence, Comparable<Ope
         if (key.getVersion() == 4) {
             return new OpenPgpV4Fingerprint(key);
         }
+        if (key.getVersion() == 5) {
+            return new OpenPgpV5Fingerprint(key);
+        }
         throw new IllegalArgumentException("OpenPGP keys of version " + key.getVersion() + " are not supported.");
     }
 

pgpainless-core/src/main/java/org/pgpainless/key/OpenPgpV4Fingerprint.java

@@ -26,51 +26,13 @@ public class OpenPgpV4Fingerprint extends OpenPgpFingerprint {
 
     /**
      * Create an {@link OpenPgpV4Fingerprint}.
-     * @see <a href="https://xmpp.org/extensions/xep-0373.html#annoucning-pubkey">
-     *     XEP-0373 §4.1: The OpenPGP Public-Key Data Node about how to obtain the fingerprint</a>
-     * @param fingerprint hexadecimal representation of the fingerprint.
+     *
+     * @param fingerprint uppercase hexadecimal fingerprint of length 40
      */
     public OpenPgpV4Fingerprint(@Nonnull String fingerprint) {
         super(fingerprint);
     }
 
-    @Override
-    public int getVersion() {
-        return 4;
-    }
-
-    @Override
-    protected boolean isValid(@Nonnull String fp) {
-        return fp.matches("[0-9A-F]{40}");
-    }
-
-    @Override
-    public long getKeyId() {
-        byte[] bytes = Hex.decode(toString().getBytes(utf8));
-        ByteBuffer buf = ByteBuffer.wrap(bytes);
-
-        // We have to cast here in order to be compatible with java 8
-        // https://github.com/eclipse/jetty.project/issues/3244
-        ((Buffer) buf).position(12);
-
-        return buf.getLong();
-    }
-
-    @Override
-    public String prettyPrint() {
-        String fp = toString();
-        StringBuilder pretty = new StringBuilder();
-        for (int i = 0; i < 5; i++) {
-            pretty.append(fp, i * 4, (i + 1) * 4).append(' ');
-        }
-        pretty.append(' ');
-        for (int i = 5; i < 9; i++) {
-            pretty.append(fp, i * 4, (i + 1) * 4).append(' ');
-        }
-        pretty.append(fp, 36, 40);
-        return pretty.toString();
-    }
-
     public OpenPgpV4Fingerprint(@Nonnull byte[] bytes) {
         super(Hex.encode(bytes));
     }
@@ -95,6 +57,44 @@ public class OpenPgpV4Fingerprint extends OpenPgpFingerprint {
         super(ring);
     }
 
+    @Override
+    public int getVersion() {
+        return 4;
+    }
+
+    @Override
+    protected boolean isValid(@Nonnull String fp) {
+        return fp.matches("^[0-9A-F]{40}$");
+    }
+
+    @Override
+    public long getKeyId() {
+        byte[] bytes = Hex.decode(toString().getBytes(utf8));
+        ByteBuffer buf = ByteBuffer.wrap(bytes);
+
+        // The key id is the right-most 8 bytes (conveniently a long)
+        // We have to cast here in order to be compatible with java 8
+        // https://github.com/eclipse/jetty.project/issues/3244
+        ((Buffer) buf).position(12); // 20 - 8 bytes = offset 12
+
+        return buf.getLong();
+    }
+
+    @Override
+    public String prettyPrint() {
+        String fp = toString();
+        StringBuilder pretty = new StringBuilder();
+        for (int i = 0; i < 5; i++) {
+            pretty.append(fp, i * 4, (i + 1) * 4).append(' ');
+        }
+        pretty.append(' ');
+        for (int i = 5; i < 9; i++) {
+            pretty.append(fp, i * 4, (i + 1) * 4).append(' ');
+        }
+        pretty.append(fp, 36, 40);
+        return pretty.toString();
+    }
+
     @Override
     public boolean equals(Object other) {
         if (other == null) {

pgpainless-core/src/main/java/org/pgpainless/key/OpenPgpV5Fingerprint.java

@@ -0,0 +1,117 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.key;
+
+import org.bouncycastle.openpgp.PGPKeyRing;
+import org.bouncycastle.openpgp.PGPPublicKey;
+import org.bouncycastle.openpgp.PGPPublicKeyRing;
+import org.bouncycastle.openpgp.PGPSecretKey;
+import org.bouncycastle.openpgp.PGPSecretKeyRing;
+import org.bouncycastle.util.encoders.Hex;
+
+import javax.annotation.Nonnull;
+import java.nio.Buffer;
+import java.nio.ByteBuffer;
+
+/**
+ * This class represents a hex encoded, upper case OpenPGP v5 fingerprint.
+ */
+public class OpenPgpV5Fingerprint extends OpenPgpFingerprint {
+
+    /**
+     * Create an {@link OpenPgpV5Fingerprint}.
+     *
+     * @param fingerprint uppercase hexadecimal fingerprint of length 64
+     */
+    public OpenPgpV5Fingerprint(@Nonnull String fingerprint) {
+        super(fingerprint);
+    }
+
+    public OpenPgpV5Fingerprint(@Nonnull byte[] bytes) {
+        super(Hex.encode(bytes));
+    }
+
+    public OpenPgpV5Fingerprint(@Nonnull PGPPublicKey key) {
+        super(key);
+    }
+
+    public OpenPgpV5Fingerprint(@Nonnull PGPSecretKey key) {
+        this(key.getPublicKey());
+    }
+
+    public OpenPgpV5Fingerprint(@Nonnull PGPPublicKeyRing ring) {
+        super(ring);
+    }
+
+    public OpenPgpV5Fingerprint(@Nonnull PGPSecretKeyRing ring) {
+        super(ring);
+    }
+
+    public OpenPgpV5Fingerprint(@Nonnull PGPKeyRing ring) {
+        super(ring);
+    }
+
+    @Override
+    public int getVersion() {
+        return 5;
+    }
+
+    @Override
+    protected boolean isValid(@Nonnull String fp) {
+        return fp.matches("^[0-9A-F]{64}$");
+    }
+
+    @Override
+    public long getKeyId() {
+        byte[] bytes = Hex.decode(toString().getBytes(utf8));
+        ByteBuffer buf = ByteBuffer.wrap(bytes);
+
+        // The key id is the left-most 8 bytes (conveniently a long).
+        // We have to cast here in order to be compatible with java 8
+        // https://github.com/eclipse/jetty.project/issues/3244
+        ((Buffer) buf).position(0);
+
+        return buf.getLong();
+    }
+
+    @Override
+    public String prettyPrint() {
+        String fp = toString();
+        StringBuilder pretty = new StringBuilder();
+
+        for (int i = 0; i < 4; i++) {
+            pretty.append(fp, i * 8, (i + 1) * 8).append(' ');
+        }
+        pretty.append(' ');
+        for (int i = 4; i < 7; i++) {
+            pretty.append(fp, i * 8, (i + 1) * 8).append(' ');
+        }
+        pretty.append(fp, 56, 64);
+        return pretty.toString();
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (other == null) {
+            return false;
+        }
+
+        if (!(other instanceof CharSequence)) {
+            return false;
+        }
+
+        return this.toString().equals(other.toString());
+    }
+
+    @Override
+    public int hashCode() {
+        return toString().hashCode();
+    }
+
+    @Override
+    public int compareTo(OpenPgpFingerprint openPgpFingerprint) {
+        return toString().compareTo(openPgpFingerprint.toString());
+    }
+}

pgpainless-core/src/test/java/org/pgpainless/key/OpenPgpV5FingerprintTest.java

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.key;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class OpenPgpV5FingerprintTest {
+
+    @Test
+    public void testFingerprintFormatting() {
+        String pretty = "76543210 ABCDEFAB 01AB23CD 1C0FFEE1  1EEFF0C1 DC32BA10 BAFEDCBA 01234567";
+        String fp = pretty.replace(" ", "");
+
+        OpenPgpV5Fingerprint fingerprint = new OpenPgpV5Fingerprint(fp);
+        assertEquals(fp, fingerprint.toString());
+        assertEquals(pretty, fingerprint.prettyPrint());
+
+        long id = fingerprint.getKeyId();
+        assertEquals("76543210abcdefab", Long.toHexString(id));
+    }
+}