secp256k1-bitcoinj: Move WitnessMaker to src/main from src/test

bitcoinj · Mar 4, 2024 · bf0b94c · bf0b94c
1 parent 5e15025
commit bf0b94c
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Showing 3 changed files with 71 additions and 49 deletions.
diff --git a/secp256k1-bitcoinj/src/main/java/org/bitcoinj/secp256k1/bitcoinj/WitnessMaker.java b/secp256k1-bitcoinj/src/main/java/org/bitcoinj/secp256k1/bitcoinj/WitnessMaker.java
@@ -0,0 +1,63 @@
+package org.bitcoinj.secp256k1.bitcoinj;
+
+import org.bitcoinj.secp256k1.api.P256K1XOnlyPubKey;
+import org.bitcoinj.secp256k1.api.P256k1PubKey;
+import org.bitcoinj.secp256k1.api.Secp256k1;
+import org.bitcoinj.secp256k1.foreign.PubKeyPojo;
+
+import java.math.BigInteger;
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+/**
+ * Experimental class for making P2TR witness programs
+ */
+public class WitnessMaker {
+    /**
+     * 64-byte concatenation of two 32-byte hashes of "TapTweak"
+     */
+    private static final byte[] tweakPrefix = calcTagPrefix64("TapTweak");
+    private final Secp256k1 secp;
+
+    public WitnessMaker(Secp256k1 secp) {
+        this.secp = secp;
+    }
+
+    public byte[] calcWitnessProgram(P256k1PubKey pubKey) {
+        P256K1XOnlyPubKey xOnlyKey = pubKey.getXOnly();
+        BigInteger tweakInt = calcTweak(xOnlyKey);
+        P256k1PubKey G = new PubKeyPojo(Secp256k1.EC_PARAMS.getGenerator());
+        P256k1PubKey P2 = secp.ecPubKeyTweakMul(G, tweakInt);
+        P256k1PubKey Q = secp.ecPubKeyCombine(pubKey, P2);
+        return Q.getXOnly().getSerialized();
+    }
+
+    public static BigInteger calcTweak(P256K1XOnlyPubKey xOnlyPubKey) {
+        var digest = newDigest();
+        digest.update(tweakPrefix);
+        byte[] hash = digest.digest(xOnlyPubKey.getSerialized());
+        return new BigInteger(1, hash);
+    }
+
+    public static byte[] calcTagPrefix64(String tag) {
+        byte[] hash = hash256(tag.getBytes(StandardCharsets.UTF_8));
+        return ByteBuffer.allocate(64)
+                .put(hash)
+                .put(hash)
+                .array();
+    }
+
+    private static byte[] hash256(byte[] message) {
+        return newDigest().digest(message);
+    }
+
+    private static MessageDigest newDigest() {
+        try {
+            return MessageDigest.getInstance("SHA-256");
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException(e);  // Can't happen.
+        }
+    }
+}
diff --git a/secp256k1-bitcoinj/src/main/java/org/bitcoinj/secp256k1/bitcoinj/package-info.java b/secp256k1-bitcoinj/src/main/java/org/bitcoinj/secp256k1/bitcoinj/package-info.java
@@ -0,0 +1,6 @@
+/**
+ * This module contains experimental utility classes for integrating {@code secp256k1-jdk} with <b>bitcoinj</b>.
+ * If/when a future version of bitcoinj supports secp256k1-jdk and/or Schnorr signatures, this package will likely
+ * no longer be needed and will be deprecated.
+ */
+package org.bitcoinj.secp256k1.bitcoinj;
diff --git a/secp256k1-bitcoinj/src/test/java/org/bitcoinj/secp256k1/bitcoinj/AddressTest.java b/secp256k1-bitcoinj/src/test/java/org/bitcoinj/secp256k1/bitcoinj/AddressTest.java
@@ -21,14 +21,12 @@
 import org.junit.jupiter.params.provider.MethodSource;
 
 import java.math.BigInteger;
-import java.nio.ByteBuffer;
-import java.nio.charset.StandardCharsets;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
 import java.security.spec.ECPoint;
 import java.util.HexFormat;
 import java.util.stream.Stream;
 
+import static org.bitcoinj.secp256k1.bitcoinj.WitnessMaker.calcTweak;
+
 /**
  *
  */
@@ -117,49 +115,4 @@ void createAddressTest2() throws Exception {
         System.out.println(tapRootAddress);
     }
 
-    public class WitnessMaker {
-        private final Secp256k1 secp;
-
-        public WitnessMaker(Secp256k1 secp) {
-            this.secp = secp;
-        }
-
-        public byte[] calcWitnessProgram(P256k1PubKey pubKey) {
-            P256K1XOnlyPubKey xOnlyKey = pubKey.getXOnly();
-            BigInteger tweakInt = calcTweak(xOnlyKey);
-            P256k1PubKey G = new PubKeyPojo(Secp256k1.EC_PARAMS.getGenerator());
-            P256k1PubKey P2 = secp.ecPubKeyTweakMul(G, tweakInt);
-            P256k1PubKey Q = secp.ecPubKeyCombine(pubKey, P2);
-            return Q.getXOnly().getSerialized();
-        }
-    }
-
-    private BigInteger calcTweak(P256K1XOnlyPubKey xOnlyPubKey) {
-        var digest = newDigest();
-        digest.update(tweakPrefix);
-        byte[] hash  = digest.digest(xOnlyPubKey.getSerialized());
-        return new BigInteger(1, hash);
-    }
-
-    /** 64-byte concatenation of two 32-byte hashes of "TapTweak" */
-    private static final byte[] tweakPrefix =  calcTagPrefix64("TapTweak");
-
-    public static byte[] calcTagPrefix64(String tag) {
-        byte[] hash = hash256(tag.getBytes(StandardCharsets.UTF_8));
-        return ByteBuffer.allocate(64)
-                .put(hash)
-                .put(hash)
-                .array();
-    }
-    private static byte[] hash256(byte[] message) {
-        return newDigest().digest(message);
-    }
-
-    private static MessageDigest newDigest() {
-        try {
-            return MessageDigest.getInstance("SHA-256");
-        } catch (NoSuchAlgorithmException e) {
-            throw new RuntimeException(e);  // Can't happen.
-        }
-    }
 }