Add extension methods to PGPKeyRing, PGPSecretKeyRing and PGPSignature

pgpainless-core/src/main/kotlin/org/bouncycastle/extensions/PGPKeyRingExtensions.kt

@@ -5,6 +5,10 @@
 package org.bouncycastle.extensions
 
 import org.bouncycastle.openpgp.PGPKeyRing
+import org.bouncycastle.openpgp.PGPOnePassSignature
+import org.bouncycastle.openpgp.PGPPublicKey
+import org.bouncycastle.openpgp.PGPSignature
+import org.pgpainless.key.OpenPgpFingerprint
 import org.pgpainless.key.SubkeyIdentifier
 
 /**
@@ -12,4 +16,46 @@ import org.pgpainless.key.SubkeyIdentifier
  */
 fun PGPKeyRing.matches(subkeyIdentifier: SubkeyIdentifier): Boolean =
         this.publicKey.keyID == subkeyIdentifier.primaryKeyId &&
-                this.getPublicKey(subkeyIdentifier.subkeyId) != null
+                this.getPublicKey(subkeyIdentifier.subkeyId) != null
+
+/**
+ * Return true, if the [PGPKeyRing] contains a public key with the given key-ID.
+ *
+ * @param keyId keyId
+ * @return true if key with the given key-ID is present, false otherwise
+ */
+fun PGPKeyRing.hasPublicKey(keyId: Long): Boolean =
+        this.getPublicKey(keyId) != null
+
+/**
+ * Return true, if the [PGPKeyRing] contains a public key with the given fingerprint.
+ *
+ * @param fingerprint fingerprint
+ * @return true if key with the given fingerprint is present, false otherwise
+ */
+fun PGPKeyRing.hasPublicKey(fingerprint: OpenPgpFingerprint): Boolean =
+        this.getPublicKey(fingerprint) != null
+
+/**
+ * Return the [PGPPublicKey] with the given [OpenPgpFingerprint] or null, if no such key is present.
+ *
+ * @param fingerprint fingerprint
+ * @return public key
+ */
+fun PGPKeyRing.getPublicKey(fingerprint: OpenPgpFingerprint): PGPPublicKey? =
+        this.getPublicKey(fingerprint.bytes)
+
+/**
+ * Return the [PGPPublicKey] that matches the [OpenPgpFingerprint] of the given [PGPSignature].
+ * If the [PGPSignature] does not carry an issuer-fingerprint subpacket, fall back to the issuer-keyID subpacket to
+ * identify the [PGPPublicKey] via its key-ID.
+ */
+fun PGPKeyRing.getPublicKeyFor(signature: PGPSignature): PGPPublicKey? =
+        signature.getFingerprint()?.let { this.getPublicKey(it) } ?:
+        this.getPublicKey(signature.keyID)
+
+/**
+ * Return the [PGPPublicKey] that matches the key-ID of the given [PGPOnePassSignature] packet.
+ */
+fun PGPKeyRing.getPublicKeyFor(onePassSignature: PGPOnePassSignature): PGPPublicKey? =
+        this.getPublicKey(onePassSignature.keyID)

pgpainless-core/src/main/kotlin/org/bouncycastle/extensions/PGPSecretKeyRingExtensions.kt

@@ -4,8 +4,53 @@
 
 package org.bouncycastle.extensions
 
-import org.bouncycastle.openpgp.PGPPublicKeyRing
-import org.bouncycastle.openpgp.PGPSecretKeyRing
+import org.bouncycastle.openpgp.*
+import org.pgpainless.key.OpenPgpFingerprint
 
+/**
+ * OpenPGP certificate containing the public keys of this OpenPGP key.
+ */
 val PGPSecretKeyRing.certificate: PGPPublicKeyRing
-    get() = PGPPublicKeyRing(this.publicKeys.asSequence().toList())
+    get() = PGPPublicKeyRing(this.publicKeys.asSequence().toList())
+
+/**
+ * Return true, if the [PGPSecretKeyRing] contains a [PGPSecretKey] with the given key-ID.
+ *
+ * @param keyId keyId of the secret key
+ * @return true, if the [PGPSecretKeyRing] has a matching [PGPSecretKey], false otherwise
+ */
+fun PGPSecretKeyRing.hasSecretKey(keyId: Long): Boolean =
+        this.getSecretKey(keyId) != null
+
+/**
+ * Return true, if the [PGPSecretKeyRing] contains a [PGPSecretKey] with the given fingerprint.
+ *
+ * @param fingerprint fingerprint
+ * @return true, if the [PGPSecretKeyRing] has a matching [PGPSecretKey], false otherwise
+ */
+fun PGPSecretKeyRing.hasSecretKey(fingerprint: OpenPgpFingerprint): Boolean =
+        this.getSecretKey(fingerprint) != null
+
+/**
+ * Return the [PGPSecretKey] with the given [OpenPgpFingerprint].
+ *
+ * @param fingerprint fingerprint of the secret key
+ * @return the secret key or null
+ */
+fun PGPSecretKeyRing.getSecretKey(fingerprint: OpenPgpFingerprint): PGPSecretKey? =
+        this.getSecretKey(fingerprint.bytes)
+
+/**
+ * Return the [PGPSecretKey] that matches the [OpenPgpFingerprint] of the given [PGPSignature].
+ * If the [PGPSignature] does not carry an issuer-fingerprint subpacket, fall back to the issuer-keyID subpacket to
+ * identify the [PGPSecretKey] via its key-ID.
+ */
+fun PGPSecretKeyRing.getSecretKeyFor(signature: PGPSignature): PGPSecretKey? =
+        signature.getFingerprint()?.let { this.getSecretKey(it) } ?:
+        this.getSecretKey(signature.keyID)
+
+/**
+ * Return the [PGPSecretKey] that matches the key-ID of the given [PGPOnePassSignature] packet.
+ */
+fun PGPSecretKeyRing.getSecretKeyFor(onePassSignature: PGPOnePassSignature): PGPSecretKey? =
+        this.getSecretKey(onePassSignature.keyID)

pgpainless-core/src/main/kotlin/org/bouncycastle/extensions/PGPSignatureExtensions.kt

@@ -8,6 +8,7 @@ import org.bouncycastle.openpgp.PGPSignature
 import org.pgpainless.algorithm.RevocationState
 import org.pgpainless.key.OpenPgpFingerprint
 import org.pgpainless.signature.SignatureUtils
+import org.pgpainless.signature.subpackets.SignatureSubpacketsUtil
 import java.util.*
 
 /**
@@ -51,3 +52,6 @@ fun PGPSignature?.toRevocationState() =
         else
             if (isHardRevocation()) RevocationState.hardRevoked()
             else RevocationState.softRevoked(creationTime)
+
+fun PGPSignature.getFingerprint(): OpenPgpFingerprint? =
+        SignatureSubpacketsUtil.getIssuerFingerprintAsOpenPgpFingerprint(this)

pgpainless-core/src/main/kotlin/org/pgpainless/key/OpenPgpFingerprint.kt

@@ -16,6 +16,7 @@ import java.nio.charset.Charset
  */
 abstract class OpenPgpFingerprint : CharSequence, Comparable<OpenPgpFingerprint> {
     val fingerprint: String
+    val bytes: ByteArray
 
     /**
      * Return the version of the fingerprint.
@@ -41,6 +42,7 @@ abstract class OpenPgpFingerprint : CharSequence, Comparable<OpenPgpFingerprint>
             throw IllegalArgumentException("Fingerprint '$fingerprint' does not appear to be a valid OpenPGP V${getVersion()} fingerprint.")
         }
         this.fingerprint = prep
+        this.bytes = Hex.decode(prep)
     }
 
     constructor(bytes: ByteArray): this(Hex.toHexString(bytes))