KeyCrypterException: Introduce dedicated PublicPrivateMismatch exception for when a private key or seed is decrypted, it doesn't match its public key.

core/src/main/java/org/bitcoinj/crypto/DeterministicKey.java

@@ -377,7 +377,7 @@ public class DeterministicKey extends ECKey {
         BigInteger privKey = findOrDeriveEncryptedPrivateKey(keyCrypter, aesKey);
         DeterministicKey key = new DeterministicKey(childNumberPath, chainCode, privKey, parent);
         if (!Arrays.equals(key.getPubKey(), getPubKey()))
-            throw new KeyCrypterException("Provided AES key is wrong");
+            throw new KeyCrypterException.PublicPrivateMismatch("Provided AES key is wrong");
         if (parent == null)
             key.setCreationTimeSeconds(getCreationTimeSeconds());
         return key;
@@ -436,7 +436,7 @@ public class DeterministicKey extends ECKey {
         // If it's not, it means we tried decrypting with an invalid password and earlier checks e.g. for padding didn't
         // catch it.
         if (!downCursor.pub.equals(pub))
-            throw new KeyCrypterException("Could not decrypt bytes");
+            throw new KeyCrypterException.PublicPrivateMismatch("Could not decrypt bytes");
         return checkNotNull(downCursor.priv);
     }
 

core/src/main/java/org/bitcoinj/crypto/KeyCrypterException.java

@@ -28,11 +28,25 @@ package org.bitcoinj.crypto;
 public class KeyCrypterException extends RuntimeException {
     private static final long serialVersionUID = -4441989608332681377L;
 
-    public KeyCrypterException(String s) {
+    public KeyCrypterException(String message) {
-        super(s);
+        super(message);
     }
 
-    public KeyCrypterException(String s, Throwable throwable) {
+    public KeyCrypterException(String message, Throwable throwable) {
-        super(s, throwable);
+        super(message, throwable);
+    }
+
+    /**
+     * This exception is thrown when a private key or seed is decrypted, it doesn't match its public key any
+     * more. This likely means the wrong decryption key has been used.
+     */
+    public static class PublicPrivateMismatch extends KeyCrypterException {
+        public PublicPrivateMismatch(String message) {
+            super(message);
+        }
+
+        public PublicPrivateMismatch(String message, Throwable throwable) {
+            super(message, throwable);
+        }
     }
 }

core/src/main/java/org/bitcoinj/wallet/DeterministicKeyChain.java

@@ -1014,7 +1014,7 @@ public class DeterministicKeyChain implements EncryptableKeyChain {
         DeterministicKeyChain chain = makeKeyChainFromSeed(decSeed, getAccountPath(), outputScriptType);
         // Now double check that the keys match to catch the case where the key is wrong but padding didn't catch it.
         if (!chain.getWatchingKey().getPubKeyPoint().equals(getWatchingKey().getPubKeyPoint()))
-            throw new KeyCrypterException("Provided AES key is wrong");
+            throw new KeyCrypterException.PublicPrivateMismatch("Provided AES key is wrong");
         chain.lookaheadSize = lookaheadSize;
         // Now copy the (pubkey only) leaf keys across to avoid rederiving them. The private key bytes are missing
         // anyway so there's nothing to decrypt.