PGPSignature: Add isRevocation, isHardRevocation methods

Author: vanitasvitae

pg/src/main/java/org/bouncycastle/openpgp/PGPSignature.java

@@ -23,6 +23,8 @@
 import org.bouncycastle.bcpg.TrustPacket;
 import org.bouncycastle.bcpg.sig.IssuerFingerprint;
 import org.bouncycastle.bcpg.sig.IssuerKeyID;
+import org.bouncycastle.bcpg.sig.RevocationReason;
+import org.bouncycastle.bcpg.sig.RevocationReasonTags;
 import org.bouncycastle.math.ec.rfc8032.Ed25519;
 import org.bouncycastle.math.ec.rfc8032.Ed448;
 import org.bouncycastle.openpgp.operator.PGPContentVerifier;
@@ -905,6 +907,37 @@ public static boolean isCertification(int signatureType)
             || PGPSignature.POSITIVE_CERTIFICATION == signatureType;
     }
 
+    public static boolean isRevocation(int signatureType)
+    {
+        return PGPSignature.KEY_REVOCATION == signatureType
+                || PGPSignature.CERTIFICATION_REVOCATION == signatureType
+                || PGPSignature.SUBKEY_REVOCATION == signatureType;
+    }
+
+    public boolean isHardRevocation()
+    {
+        if (!isRevocation(getSignatureType()))
+        {
+            return false; // no revocation
+        }
+
+        if (!hasSubpackets())
+        {
+            return true; // consider missing subpackets (and therefore missing reason) as hard revocation
+        }
+
+        // only consider reasons from the hashed packet area
+        RevocationReason reason = getHashedSubPackets() != null ?
+                getHashedSubPackets().getRevocationReason() : null;
+        if (reason == null)
+        {
+            return true; // missing reason packet is hard
+        }
+
+        return reason.getRevocationReason() == RevocationReasonTags.NO_REASON // No reason is hard
+                || reason.getRevocationReason() == RevocationReasonTags.KEY_COMPROMISED; // key compromise is hard
+    }
+
     /**
      * Return true, if the cryptographic signature encoding of the two signatures match.
      *