diff --git a/pgpainless-core/src/main/java/org/pgpainless/algorithm/SymmetricKeyAlgorithm.java b/pgpainless-core/src/main/java/org/pgpainless/algorithm/SymmetricKeyAlgorithm.java
deleted file mode 100644
index e04f21a5..00000000
--- a/pgpainless-core/src/main/java/org/pgpainless/algorithm/SymmetricKeyAlgorithm.java
+++ /dev/null
@@ -1,150 +0,0 @@
-// SPDX-FileCopyrightText: 2018 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package org.pgpainless.algorithm;
-
-import java.util.Map;
-import java.util.NoSuchElementException;
-import java.util.concurrent.ConcurrentHashMap;
-
-import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
-
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
-
-/**
- * Enumeration of possible symmetric encryption algorithms.
- *
- * @see <a href="https://tools.ietf.org/html/rfc4880#section-9.2">RFC4880: Symmetric-Key Algorithms</a>
- */
-public enum SymmetricKeyAlgorithm {
-
-    /**
-     * Plaintext or unencrypted data.
-     */
-    NULL            (SymmetricKeyAlgorithmTags.NULL),
-
-    /**
-     * IDEA is deprecated.
-     * @deprecated use a different algorithm.
-     */
-    @Deprecated
-    IDEA            (SymmetricKeyAlgorithmTags.IDEA),
-
-    /**
-     * TripleDES (DES-EDE - 168 bit key derived from 192).
-     */
-    TRIPLE_DES      (SymmetricKeyAlgorithmTags.TRIPLE_DES),
-
-    /**
-     * CAST5 (128-bit key, as per RFC2144).
-     */
-    CAST5           (SymmetricKeyAlgorithmTags.CAST5),
-
-    /**
-     * Blowfish (128-bit key, 16 rounds).
-     */
-    BLOWFISH        (SymmetricKeyAlgorithmTags.BLOWFISH),
-
-    /**
-     * Reserved in RFC4880.
-     * SAFER-SK128 (13 rounds)
-     */
-    SAFER           (SymmetricKeyAlgorithmTags.SAFER),
-
-    /**
-     * Reserved in RFC4880.
-     * Reserved for DES/SK
-     */
-    DES             (SymmetricKeyAlgorithmTags.DES),
-
-    /**
-     * AES with 128-bit key.
-     */
-    AES_128         (SymmetricKeyAlgorithmTags.AES_128),
-
-    /**
-     * AES with 192-bit key.
-     */
-    AES_192         (SymmetricKeyAlgorithmTags.AES_192),
-
-    /**
-     * AES with 256-bit key.
-     */
-    AES_256         (SymmetricKeyAlgorithmTags.AES_256),
-
-    /**
-     * Twofish with 256-bit key.
-     */
-    TWOFISH         (SymmetricKeyAlgorithmTags.TWOFISH),
-
-    /**
-     * Reserved for Camellia with 128-bit key.
-     */
-    CAMELLIA_128    (SymmetricKeyAlgorithmTags.CAMELLIA_128),
-
-    /**
-     * Reserved for Camellia with 192-bit key.
-     */
-    CAMELLIA_192    (SymmetricKeyAlgorithmTags.CAMELLIA_192),
-
-    /**
-     * Reserved for Camellia with 256-bit key.
-     */
-    CAMELLIA_256    (SymmetricKeyAlgorithmTags.CAMELLIA_256),
-    ;
-
-    private static final Map<Integer, SymmetricKeyAlgorithm> MAP = new ConcurrentHashMap<>();
-
-    static {
-        for (SymmetricKeyAlgorithm s : SymmetricKeyAlgorithm.values()) {
-            MAP.put(s.algorithmId, s);
-        }
-    }
-
-    /**
-     * Return the {@link SymmetricKeyAlgorithm} enum that corresponds to the provided numeric id.
-     * If an invalid id is provided, null is returned.
-     *
-     * @param id numeric algorithm id
-     * @return symmetric key algorithm enum
-     */
-    @Nullable
-    public static SymmetricKeyAlgorithm fromId(int id) {
-        return MAP.get(id);
-    }
-
-    /**
-     * Return the {@link SymmetricKeyAlgorithm} enum that corresponds to the provided numeric id.
-     * If an invalid id is provided, throw a {@link NoSuchElementException}.
-     *
-     * @param id numeric algorithm id
-     * @return symmetric key algorithm enum
-     *
-     * @throws NoSuchElementException if an unmatched id is provided
-     */
-    @Nonnull
-    public static SymmetricKeyAlgorithm requireFromId(int id) {
-        SymmetricKeyAlgorithm algorithm = fromId(id);
-        if (algorithm == null) {
-            throw new NoSuchElementException("No SymmetricKeyAlgorithm found for id " + id);
-        }
-        return algorithm;
-    }
-
-    private final int algorithmId;
-
-    SymmetricKeyAlgorithm(int algorithmId) {
-        this.algorithmId = algorithmId;
-    }
-
-    /**
-     * Return the numeric algorithm id of the enum.
-     *
-     * @return numeric id
-     */
-    public int getAlgorithmId() {
-        return algorithmId;
-    }
-}
diff --git a/pgpainless-core/src/main/java/org/pgpainless/algorithm/SymmetricKeyAlgorithm.kt b/pgpainless-core/src/main/java/org/pgpainless/algorithm/SymmetricKeyAlgorithm.kt
new file mode 100644
index 00000000..ae72ff05
--- /dev/null
+++ b/pgpainless-core/src/main/java/org/pgpainless/algorithm/SymmetricKeyAlgorithm.kt
@@ -0,0 +1,120 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.algorithm
+
+/**
+ * Enumeration of possible symmetric encryption algorithms.
+ *
+ * See [RFC4880: Symmetric-Key Algorithms](https://tools.ietf.org/html/rfc4880#section-9.2)
+ */
+enum class SymmetricKeyAlgorithm(val algorithmId: Int) {
+
+    /**
+     * Plaintext or unencrypted data.
+     */
+    NULL            (0),
+
+    /**
+     * IDEA is deprecated.
+     * @deprecated use a different algorithm.
+     */
+    @Deprecated("IDEA is deprecated.")
+    IDEA            (1),
+
+    /**
+     * TripleDES (DES-EDE - 168 bit key derived from 192).
+     */
+    TRIPLE_DES      (2),
+
+    /**
+     * CAST5 (128-bit key, as per RFC2144).
+     */
+    CAST5           (3),
+
+    /**
+     * Blowfish (128-bit key, 16 rounds).
+     */
+    BLOWFISH        (4),
+
+    /**
+     * Reserved in RFC4880.
+     * SAFER-SK128 (13 rounds)
+     */
+    SAFER           (5),
+
+    /**
+     * Reserved in RFC4880.
+     * Reserved for DES/SK
+     */
+    DES             (6),
+
+    /**
+     * AES with 128-bit key.
+     */
+    AES_128         (7),
+
+    /**
+     * AES with 192-bit key.
+     */
+    AES_192         (8),
+
+    /**
+     * AES with 256-bit key.
+     */
+    AES_256         (9),
+
+    /**
+     * Twofish with 256-bit key.
+     */
+    TWOFISH         (10),
+
+    /**
+     * Reserved for Camellia with 128-bit key.
+     */
+    CAMELLIA_128    (11),
+
+    /**
+     * Reserved for Camellia with 192-bit key.
+     */
+    CAMELLIA_192    (12),
+
+    /**
+     * Reserved for Camellia with 256-bit key.
+     */
+    CAMELLIA_256    (13),
+    ;
+
+    companion object {
+
+        /**
+         * Return the [SymmetricKeyAlgorithm] enum that corresponds to the provided numeric id.
+         * If an invalid id is provided, null is returned.
+         *
+         * @param id numeric algorithm id
+         * @return symmetric key algorithm enum
+         */
+        @JvmStatic
+        fun fromId(id: Int): SymmetricKeyAlgorithm? {
+            return values().firstOrNull { 
+                it.algorithmId == id
+            }
+        }
+
+        /**
+         * Return the [SymmetricKeyAlgorithm] enum that corresponds to the provided numeric id.
+         * If an invalid id is provided, throw a [NoSuchElementException].
+         *
+         * @param id numeric algorithm id
+         * @return symmetric key algorithm enum
+         *
+         * @throws NoSuchElementException if an unmatched id is provided
+         */
+        @JvmStatic
+        fun requireFromId(id: Int): SymmetricKeyAlgorithm {
+            return fromId(id) ?:
+            throw NoSuchElementException("No SymmetricKeyAlgorithm found for id $id")
+        }
+    }
+}
\ No newline at end of file