support p2tr script type wallet creation

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

@@ -17,10 +17,7 @@ import org.bouncycastle.crypto.params.ECKeyGenerationParameters;
 import org.bouncycastle.crypto.params.ECPrivateKeyParameters;
 import org.bouncycastle.crypto.params.ECPublicKeyParameters;
 import org.bouncycastle.crypto.signers.ECDSASigner;
-import org.bouncycastle.math.ec.ECAlgorithms;
+import org.bouncycastle.math.ec.*;
-import org.bouncycastle.math.ec.ECPoint;
-import org.bouncycastle.math.ec.FixedPointCombMultiplier;
-import org.bouncycastle.math.ec.FixedPointUtil;
 import org.bouncycastle.math.ec.custom.sec.SecP256K1Curve;
 import org.bouncycastle.util.Properties;
 import org.bouncycastle.util.encoders.Hex;
@@ -30,6 +27,7 @@ import org.slf4j.LoggerFactory;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.math.BigInteger;
+import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.security.SecureRandom;
 import java.security.SignatureException;
@@ -628,6 +626,40 @@ public class ECKey implements EncryptableItem {
         }
     }
 
+    public ECKey getTweakedOutputKey() {
+        ECPoint internalKey = liftX(getPubKeyXCoord());
+        byte[] taggedHash = taggedHash("TapTweak", internalKey.getXCoord().getEncoded());
+        ECPoint outputKey = internalKey.add(ECKey.fromPrivate(taggedHash).getPubKeyPoint());
+        return ECKey.fromPublicOnly(outputKey, true);
+    }
+
+    private static ECPoint liftX(byte[] bytes) {
+        SecP256K1Curve secP256K1Curve = (SecP256K1Curve)CURVE_PARAMS.getCurve();
+        BigInteger x = new BigInteger(1, bytes);
+        BigInteger p = secP256K1Curve.getQ();
+        if(x.compareTo(p) > -1) {
+            throw new IllegalArgumentException("Provided bytes must be less than secp256k1 field size");
+        }
+
+        BigInteger y_sq = x.modPow(BigInteger.valueOf(3), p).add(BigInteger.valueOf(7)).mod(p);
+        BigInteger y = y_sq.modPow(p.add(BigInteger.valueOf(1)).divide(BigInteger.valueOf(4)), p);
+        if(!y.modPow(BigInteger.valueOf(2), p).equals(y_sq)) {
+            throw new IllegalStateException("Calculated invalid y_sq when solving for y co-ordinate");
+        }
+
+        return secP256K1Curve.createPoint(x, y.and(BigInteger.ONE).equals(BigInteger.ZERO) ? y : p.subtract(y));
+    }
+
+    private static byte[] taggedHash(String tag, byte[] msg) {
+        byte[] hash = Sha256Hash.hash(tag.getBytes(StandardCharsets.UTF_8));
+        ByteBuffer buffer = ByteBuffer.allocate(hash.length + hash.length + msg.length);
+        buffer.put(hash);
+        buffer.put(hash);
+        buffer.put(msg);
+
+        return Sha256Hash.hash(buffer.array());
+    }
+
     /**
      * Returns true if the given pubkey is canonical, i.e. the correct length taking into account compression.
      */

src/main/java/com/sparrowwallet/drongo/policy/Miniscript.java

@@ -5,6 +5,7 @@ import java.util.regex.Pattern;
 
 public class Miniscript {
     private static final Pattern SINGLE_PATTERN = Pattern.compile("pkh?\\(");
+    private static final Pattern TAPROOT_PATTERN = Pattern.compile("tr\\(");
     private static final Pattern MULTI_PATTERN = Pattern.compile("multi\\(([\\d+])");
 
     private String script;
@@ -27,6 +28,11 @@ public class Miniscript {
             return 1;
         }
 
+        Matcher taprootMatcher = TAPROOT_PATTERN.matcher(script);
+        if(taprootMatcher.find()) {
+            return 1;
+        }
+
         Matcher multiMatcher = MULTI_PATTERN.matcher(script);
         if(multiMatcher.find()) {
             String threshold = multiMatcher.group(1);

src/main/java/com/sparrowwallet/drongo/protocol/Script.java

@@ -175,6 +175,11 @@ public class Script {
             }
         }
 
+        //Special handling for taproot tweaked keys - we don't want to tweak them again
+        if(P2TR.isScriptType(this)) {
+            return new Address[] { new P2TRAddress(P2TR.getPublicKeyFromScript(this).getPubKeyXCoord()) };
+        }
+
         for(ScriptType scriptType : SINGLE_KEY_TYPES) {
             if(scriptType.isScriptType(this)) {
                 return new Address[] { scriptType.getAddress(scriptType.getPublicKeyFromScript(this)) };

src/main/java/com/sparrowwallet/drongo/protocol/ScriptType.java

@@ -975,15 +975,15 @@ public enum ScriptType {
             return List.of(MULTI, CUSTOM);
         }
     },
-    P2TR("P2TR", "Taproot (P2TR)", "m/6789'/0'/0'") {
+    P2TR("P2TR", "Taproot (P2TR)", "m/86'/0'/0'") {
         @Override
         public Address getAddress(byte[] pubKey) {
             return new P2TRAddress(pubKey);
         }
 
         @Override
-        public Address getAddress(ECKey key) {
+        public Address getAddress(ECKey derivedKey) {
-            return getAddress(key.getPubKeyXCoord());
+            return getAddress(derivedKey.getTweakedOutputKey().getPubKeyXCoord());
         }
 
         @Override
@@ -1001,8 +1001,8 @@ public enum ScriptType {
         }
 
         @Override
-        public Script getOutputScript(ECKey key) {
+        public Script getOutputScript(ECKey derivedKey) {
-            return getOutputScript(key.getPubKeyXCoord());
+            return getOutputScript(derivedKey.getTweakedOutputKey().getPubKeyXCoord());
         }
 
         @Override
@@ -1011,8 +1011,8 @@ public enum ScriptType {
         }
 
         @Override
-        public String getOutputDescriptor(ECKey key) {
+        public String getOutputDescriptor(ECKey derivedKey) {
-            return getDescriptor() + Utils.bytesToHex(key.getPubKeyXCoord()) + getCloseDescriptor();
+            return getDescriptor() + Utils.bytesToHex(derivedKey.getPubKeyXCoord()) + getCloseDescriptor();
         }
 
         @Override
@@ -1052,7 +1052,15 @@ public enum ScriptType {
 
         @Override
         public Script getScriptSig(Script scriptPubKey, ECKey pubKey, TransactionSignature signature) {
-            throw new UnsupportedOperationException("Constructing Taproot inputs is not yet supported");
+            if(!isScriptType(scriptPubKey)) {
+                throw new ProtocolException("Provided scriptPubKey is not a " + getName() + " script");
+            }
+
+            if(!scriptPubKey.equals(getOutputScript(pubKey))) {
+                throw new ProtocolException("Provided P2TR scriptPubKey does not match constructed pubkey script");
+            }
+
+            return new Script(new byte[0]);
         }
 
         @Override
@@ -1072,7 +1080,7 @@ public enum ScriptType {
 
         @Override
         public List<PolicyType> getAllowedPolicyTypes() {
-            return Collections.emptyList();
+            return Network.get() == Network.REGTEST || Network.get() == Network.SIGNET ? List.of(SINGLE) : Collections.emptyList();
         }
     };