diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpV4Fingerprint.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpV4Fingerprint.kt
index 4d05c4f9..f4bb41db 100644
--- a/pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpV4Fingerprint.kt
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpV4Fingerprint.kt
@@ -5,14 +5,11 @@
 package org.pgpainless.key
 
 import java.net.URI
-import java.nio.Buffer
-import java.nio.ByteBuffer
-import java.nio.charset.Charset
+import org.bouncycastle.bcpg.FingerprintUtil
 import org.bouncycastle.bcpg.KeyIdentifier
 import org.bouncycastle.openpgp.PGPKeyRing
 import org.bouncycastle.openpgp.PGPPublicKey
 import org.bouncycastle.openpgp.PGPSecretKey
-import org.bouncycastle.util.encoders.Hex
 
 class OpenPgpV4Fingerprint : OpenPgpFingerprint {
 
@@ -28,17 +25,7 @@ class OpenPgpV4Fingerprint : OpenPgpFingerprint {
 
     override fun getVersion() = 4
 
-    override val keyId: Long
-        get() {
-            val bytes = Hex.decode(toString().toByteArray(Charset.forName("UTF-8")))
-            val 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
-            (buf as Buffer).position(12) // 20 - 8 bytes = offset 12
-            return buf.getLong()
-        }
+    override val keyId: Long = FingerprintUtil.keyIdFromV4Fingerprint(bytes)
 
     override val keyIdentifier: KeyIdentifier = KeyIdentifier(bytes)
 
diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpV5Fingerprint.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpV5Fingerprint.kt
index df62ddef..5864bcd9 100644
--- a/pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpV5Fingerprint.kt
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpV5Fingerprint.kt
@@ -4,6 +4,7 @@
 
 package org.pgpainless.key
 
+import org.bouncycastle.bcpg.FingerprintUtil
 import org.bouncycastle.bcpg.KeyIdentifier
 import org.bouncycastle.openpgp.PGPKeyRing
 import org.bouncycastle.openpgp.PGPPublicKey
@@ -22,6 +23,8 @@ class OpenPgpV5Fingerprint : _64DigitFingerprint {
 
     constructor(bytes: ByteArray) : super(bytes)
 
+    override val keyId: Long = FingerprintUtil.keyIdFromLibrePgpFingerprint(bytes)
+
     override fun getVersion(): Int {
         return 5
     }
diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/key/_64DigitFingerprint.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/key/_64DigitFingerprint.kt
index f5447d61..465787ea 100644
--- a/pgpainless-core/src/main/kotlin/org/pgpainless/key/_64DigitFingerprint.kt
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/key/_64DigitFingerprint.kt
@@ -4,14 +4,11 @@
 
 package org.pgpainless.key
 
-import java.nio.Buffer
-import java.nio.ByteBuffer
-import java.nio.charset.Charset
+import org.bouncycastle.bcpg.FingerprintUtil
 import org.bouncycastle.bcpg.KeyIdentifier
 import org.bouncycastle.openpgp.PGPKeyRing
 import org.bouncycastle.openpgp.PGPPublicKey
 import org.bouncycastle.openpgp.PGPSecretKey
-import org.bouncycastle.util.encoders.Hex
 
 /**
  * This class represents a hex encoded, upper case OpenPGP v5 or v6 fingerprint. Since both
@@ -35,18 +32,7 @@ open class _64DigitFingerprint : OpenPgpFingerprint {
 
     constructor(keys: PGPKeyRing) : super(keys)
 
-    override val keyId: Long
-        get() {
-            val bytes = Hex.decode(fingerprint.toByteArray(Charset.forName("UTF-8")))
-            val 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
-            (buf as Buffer).position(0)
-
-            return buf.getLong()
-        }
+    override val keyId: Long = FingerprintUtil.keyIdFromV6Fingerprint(bytes)
 
     override fun getVersion(): Int {
         return -1 // might be v5 or v6