OpenPGPCertificate: Allow getting encryption keys by purpose

pg/src/main/java/org/bouncycastle/openpgp/api/OpenPGPCertificate.java

@@ -219,9 +219,9 @@ public Map<KeyIdentifier, OpenPGPSubkey> getSubkeys()
      * <pre>
      * keys = getComponentKeysWithFlag(date, KeyFlags.ENCRYPT_COMMS, KeyFlags.ENCRYPT_STORAGE);
      * </pre>
-     * If you instead want to access all keys, that have BOTH flags, you need to <pre>&amp;</pre> both flags:
+     * If you instead want to access all keys, that have BOTH flags, you need to <pre>|</pre> both flags:
      * <pre>
-     * keys = getComponentKeysWithFlag(date, KeyFlags.ENCRYPT_COMMS &amp; KeyFlags.ENCRYPT_STORAGE);
+     * keys = getComponentKeysWithFlag(date, KeyFlags.ENCRYPT_COMMS | KeyFlags.ENCRYPT_STORAGE);
      * </pre>
      *
      * @param evaluationTime reference time
@@ -906,15 +906,34 @@ public List<OpenPGPComponentKey> getEncryptionKeys()
      * @return encryption keys
      */
     public List<OpenPGPComponentKey> getEncryptionKeys(Date evaluationTime)
+    {
+        return getEncryptionKeys(evaluationTime, KeyFlags.ENCRYPT_COMMS, KeyFlags.ENCRYPT_STORAGE);
+    }
+
+    /**
+     * Return a list of all keys that are - at evaluation time - valid encryption keys and carry any of the given
+     * key flags.
+     * <b>
+     * Note: To get all keys that have EITHER flag A or B, call <pre>getEncryptionKeys(evalTime, A, B)</pre>.
+     * To instead get all keys that have BOTH flags A AND B, call <pre>getEncryptionKeys(evalTime, A | B)</pre>.
+     *
+     * @see KeyFlags
+     *
+     * @param evaluationTime evaluation time
+     * @param keyFlags key flags
+     * @return keys with the given flags
+     */
+    public List<OpenPGPComponentKey> getEncryptionKeys(Date evaluationTime, final int... keyFlags)
     {
         return filterKeys(evaluationTime, new KeyFilter()
         {
             @Override
             public boolean test(OpenPGPComponentKey key, Date time)
             {
-                return key.isEncryptionKey(time);
+                return key.isEncryptionKey(time, keyFlags);
             }
         });
+
     }
 
     /**
@@ -1334,7 +1353,7 @@ public KeyFlags getKeyFlags(Date evaluationTime)
          * Return <pre>true</pre>, if the key has any of the given key flags.
          * <p>
          * Note: To check if the key has EITHER flag A or B, call <pre>hasKeyFlags(evalTime, A, B)</pre>.
-         * To instead check, if the key has BOTH flags A AND B, call <pre>hasKeyFlags(evalTime, A &amp; B)</pre>.
+         * To instead check, if the key has BOTH flags A AND B, call <pre>hasKeyFlags(evalTime, A | B)</pre>.
          *
          * @param evaluationTime evaluation time
          * @param flags          key flags (see {@link KeyFlags} for possible values)
@@ -2132,21 +2151,36 @@ public boolean isEncryptionKey()
         }
 
         /**
-         * Return true, if the is - at evaluation time - marked as an encryption key.
+         * Return true, if the key is - at evaluation time - marked as an encryption key.
          *
          * @param evaluationTime evaluation time
          * @return true if key is an encryption key at evaluation time, false otherwise
          */
         public boolean isEncryptionKey(Date evaluationTime)
+        {
+            return isEncryptionKey(evaluationTime, KeyFlags.ENCRYPT_COMMS, KeyFlags.ENCRYPT_STORAGE);
+        }
+
+        /**
+         * Return true, if the key is - at evaluation time - marked as an encryption key and carries any of the given
+         * key flags.
+         * <b>
+         * Note: To check if the key has EITHER flag A or B, call <pre>isEncryptionKey(evalTime, A, B)</pre>.
+         * To instead check, if the key has BOTH flags A AND B, call <pre>isEncryptionKey(evalTime, A | B)</pre>.
+         *
+         * @param evaluationTime evaluation time
+         * @param keyFlags key flags
+         * @return true if the key is an encryption key for any of the given key flags
+         */
+        public boolean isEncryptionKey(Date evaluationTime, int... keyFlags)
         {
             if (!rawPubkey.isEncryptionKey())
             {
                 // Skip keys that are not encryption-capable by algorithm
                 return false;
             }
 
-            return hasKeyFlags(evaluationTime, KeyFlags.ENCRYPT_STORAGE) ||
-                hasKeyFlags(evaluationTime, KeyFlags.ENCRYPT_COMMS);
+            return hasKeyFlags(evaluationTime, keyFlags);
         }
 
         /**

pg/src/test/java/org/bouncycastle/openpgp/api/test/OpenPGPCertificateTest.java

@@ -49,6 +49,7 @@ protected void performTestWith(OpenPGPApi api)
         testSKSignsPKRevokedNoSubpacket(api);
         testPKSignsPKRevocationSuperseded(api);
         testGetPrimaryUserId(api);
+        testGetEncryptionKeysForPurpose(api);
     }
 
     private void testOpenPGPv6Key(OpenPGPApi api)
@@ -826,6 +827,49 @@ public PGPSignatureSubpacketGenerator apply(PGPSignatureSubpacketGenerator subpa
                 key.getPrimaryUserId(oneHourAgo));
     }
 
+    private void testGetEncryptionKeysForPurpose(OpenPGPApi api)
+            throws IOException {
+
+        // This cert has two separate encryption subkeys:
+        //  7415331173EF1FEA7AB2AFC0E40DE83A8CBBE4BC is for storage
+        //  95EFDD6BD87C62F0FC109C2964F5A6B5F40F379D is for comms
+        String CERT = "-----BEGIN PGP PUBLIC KEY BLOCK-----\n" +
+                "Comment: 88BF 5516 C226 5B7D 1817  03E6 1FF0 DE1E AF8B 379F\n" +
+                "\n" +
+                "mCYEaVxG2BvmBuO3v5cDQQCuGnAIuaeP0frpw7mutcMQwPkGuuAKUMKSBB8bCgA+\n" +
+                "FqEEiL9VFsImW30YFwPmH/DeHq+LN58FgmlcRtgCngkFlQoJCAsFlgIDAQAEiwkI\n" +
+                "BwknCQEJAgkDCAECmwEACgkQH/DeHq+LN5/NVHbqH098dr34p9KVQQNLXr8CITqP\n" +
+                "vLTkijVXyfZg6Lz1krs3EgEvc8nz3evyYj5xJI+Hg1kHb+ctB5myyTyEtge4JgRp\n" +
+                "XEbYG52SLEi5Biq9vn1pFgrozM2QuCqkwXtOr/0ASs0b3t20wsAnBBgbCgCTFqEE\n" +
+                "iL9VFsImW30YFwPmH/DeHq+LN58FgmlcRtgCmwJyoAQZGwoAHRahBGp6EAtdr26T\n" +
+                "x4sGLa+TQ+g71BlpBYJpXEbYAAoJEK+TQ+g71BlpkJ4VPAQeTXN88wXzLloW2WYP\n" +
+                "5w3w7Js4csGE5OynUupCNwUBcIfC+FBMuUdgqjczw4xKRLbZMgp5YLr8Ve3pG48L\n" +
+                "AAoJEB/w3h6vizefXrbECKbGBPh+c3+fFG3Au0gzkRMCsZsMaQaRWlQ1E2P/VWlo\n" +
+                "xy4JF5nCA6bSC+sFl+DTbwpgvdQlIILR9O386EcHuCYEaVxG2Blrm96fHzaN1JmO\n" +
+                "uhU0OMbiDMBYKOL3Iup+TQWzx897CMJ0BBgbCgAgFqEEiL9VFsImW30YFwPmH/De\n" +
+                "Hq+LN58FgmlcRtgCmwQACgkQH/DeHq+LN5/wOkjl+MJktOsh+COv4tAhSu2kR0iw\n" +
+                "rdY4IAEp7jlnZfx0BVMnVURSrZSge3Zw2vbQQe864GA3Y4le4CWFKm2QAwG4JgRp\n" +
+                "XEbYGUzlbIju0H0KDcLmLXsXp7CCLmkcnSjNAj9WTRW7GCJownQEGBsKACAWoQSI\n" +
+                "v1UWwiZbfRgXA+Yf8N4er4s3nwWCaVxG2AKbCAAKCRAf8N4er4s3n4+EpHlXYNzD\n" +
+                "I2OT9NpobaalDbmDMuvIu/81Uoxv+pJLkrMV+WW5be27HrH6w7YTH1TngILr4V2e\n" +
+                "jSB2HhjClk4YBw==\n" +
+                "=3S3M\n" +
+                "-----END PGP PUBLIC KEY BLOCK-----";
+
+        OpenPGPCertificate cert = api.readKeyOrCertificate().parseCertificate(CERT);
+
+        List<OpenPGPCertificate.OpenPGPComponentKey> allEncryptionKeys = cert.getEncryptionKeys();
+        isEquals(2, allEncryptionKeys.size());
+
+        List<OpenPGPCertificate.OpenPGPComponentKey> storageEncKeys = cert.getEncryptionKeys(new Date(), KeyFlags.ENCRYPT_STORAGE);
+        isEquals(1, storageEncKeys.size());
+        isEquals(new KeyIdentifier("7415331173EF1FEA7AB2AFC0E40DE83A8CBBE4BC"), storageEncKeys.get(0).getKeyIdentifier());
+
+        List<OpenPGPCertificate.OpenPGPComponentKey> commEncKeys = cert.getEncryptionKeys(new Date(), KeyFlags.ENCRYPT_COMMS);
+        isEquals(1, commEncKeys.size());
+        isEquals(new KeyIdentifier("95EFDD6BD87C62F0FC109C2964F5A6B5F40F379D"), commEncKeys.get(0).getKeyIdentifier());
+    }
+
     public static class TestSignature
     {
         private final PGPSignature signature;