add tapsigner, minor refactoring

src/main/java/com/sparrowwallet/drongo/Utils.java

@@ -128,6 +128,20 @@ public class Utils {
         return c;
     }
 
+    public static byte[] xor(byte[] a, byte[] b) {
+        if(a.length != b.length) {
+            throw new IllegalArgumentException("Invalid length for xor: " + a.length + " vs " + b.length);
+        }
+
+        byte[] ret = new byte[a.length];
+
+        for(int i = 0; i < a.length; i++) {
+            ret[i] = (byte) ((int) b[i] ^ (int) a[i]);
+        }
+
+        return ret;
+    }
+
     /** Parse 4 bytes from the byte array (starting at the offset) as unsigned 32-bit integer in little endian format. */
     public static long readUint32(byte[] bytes, int offset) {
         return (bytes[offset] & 0xffl) |

src/main/java/com/sparrowwallet/drongo/bip47/PaymentCode.java

@@ -20,6 +20,8 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 
+import static com.sparrowwallet.drongo.Utils.xor;
+
 public class PaymentCode {
     private static final Logger log = LoggerFactory.getLogger(PaymentCode.class);
 
@@ -313,21 +315,6 @@ public class PaymentCode {
         return HDKeyDerivation.createMasterPubKeyFromBytes(pubkey, chain);
     }
 
-    private static byte[] xor(byte[] a, byte[] b) {
-        if(a.length != b.length) {
-            log.error("Invalid length for xor: " + a.length + " vs " + b.length);
-            return null;
-        }
-
-        byte[] ret = new byte[a.length];
-
-        for(int i = 0; i < a.length; i++) {
-            ret[i] = (byte) ((int) b[i] ^ (int) a[i]);
-        }
-
-        return ret;
-    }
-
     public boolean isValid() {
         try {
             byte[] pcodeBytes = Base58.decodeChecked(strPaymentCode);

src/main/java/com/sparrowwallet/drongo/crypto/ECKey.java

@@ -627,6 +627,14 @@ public class ECKey {
             // This is what you get back from Bouncy Castle if base64 doesn't decode :(
             throw new SignatureException("Could not decode base64", e);
         }
+        byte[] messageBytes = formatMessageForSigning(message);
+        // Note that the C++ code doesn't actually seem to specify any character encoding. Presumably it's whatever
+        // JSON-SPIRIT hands back. Assume UTF-8 for now.
+        Sha256Hash messageHash = Sha256Hash.twiceOf(messageBytes);
+        return signedHashToKey(messageHash, signatureEncoded, electrumFormat);
+    }
+
+    public static ECKey signedHashToKey(Sha256Hash messageHash, byte[] signatureEncoded, boolean electrumFormat) throws SignatureException {
         // Parse the signature bytes into r/s and the selector value.
         if(signatureEncoded.length < 65) {
             throw new SignatureException("Signature truncated, expected 65 bytes and got " + signatureEncoded.length);
@@ -640,10 +648,7 @@ public class ECKey {
         BigInteger r = new BigInteger(1, Arrays.copyOfRange(signatureEncoded, 1, 33));
         BigInteger s = new BigInteger(1, Arrays.copyOfRange(signatureEncoded, 33, 65));
         ECDSASignature sig = new ECDSASignature(r, s);
-        byte[] messageBytes = formatMessageForSigning(message);
+
-        // Note that the C++ code doesn't actually seem to specify any character encoding. Presumably it's whatever
-        // JSON-SPIRIT hands back. Assume UTF-8 for now.
-        Sha256Hash messageHash = Sha256Hash.twiceOf(messageBytes);
         boolean compressed = false;
         if(header >= 39) { // this is a bech32 signature
             header -= 12;

src/main/java/com/sparrowwallet/drongo/wallet/WalletModel.java

@@ -3,7 +3,7 @@ package com.sparrowwallet.drongo.wallet;
 import java.util.Locale;
 
 public enum WalletModel {
-    SEED, SPARROW, BITCOIN_CORE, ELECTRUM, TREZOR_1, TREZOR_T, COLDCARD, LEDGER_NANO_S, LEDGER_NANO_X, DIGITALBITBOX_01, KEEPKEY, SPECTER_DESKTOP, COBO_VAULT, BITBOX_02, SPECTER_DIY, PASSPORT, BLUE_WALLET, KEYSTONE, SEEDSIGNER, CARAVAN, GORDIAN_SEED_TOOL, JADE, LEDGER_NANO_S_PLUS, EPS;
+    SEED, SPARROW, BITCOIN_CORE, ELECTRUM, TREZOR_1, TREZOR_T, COLDCARD, LEDGER_NANO_S, LEDGER_NANO_X, DIGITALBITBOX_01, KEEPKEY, SPECTER_DESKTOP, COBO_VAULT, BITBOX_02, SPECTER_DIY, PASSPORT, BLUE_WALLET, KEYSTONE, SEEDSIGNER, CARAVAN, GORDIAN_SEED_TOOL, JADE, LEDGER_NANO_S_PLUS, EPS, TAPSIGNER;
 
     public static WalletModel getModel(String model) {
         return valueOf(model.toUpperCase(Locale.ROOT));