Treat SIGHASH_ALL seperate from SIGHASH_DEFAULT

peercoin · Oct 12, 2023 · a3680c4 · a3680c4
1 parent ca018b5
commit a3680c4
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Showing 2 changed files with 20 additions and 14 deletions.
diff --git a/coinlib/lib/src/tx/sighash/taproot_signature_hasher.dart b/coinlib/lib/src/tx/sighash/taproot_signature_hasher.dart
@@ -17,31 +17,32 @@ final class TaprootSignatureHasher with Writable implements SignatureHasher {
   final PrevOutSignatureHashes? prevOutHashes;
   final int inputN;
   final List<Output> prevOuts;
-  final SigHashType hashType;
+  final SigHashType? hashType;
   final Uint8List? leafHash;
   final int codeSeperatorPos;
 
   /// Produces the hash for a Taproot input signature at [inputN].
   /// Unless [SigHashType.anyonecanpay] is true, [prevOuts] must contain the
   /// full list of previous outputs being spent.
-  /// The [hashType] controls what data is included. [SigHashType.all] shall be
-  /// encoded as SIGHASH_DEFAULT (0).
+  /// The [hashType] controls what data is included. If ommitted it will be
+  /// treated as SIGHASH_DEFAULT which includes the same data as SIGHASH_ALL but
+  /// produces distinct signatures.
   /// If an input is being signed for a tapscript, the [leafHash] must be
   /// provided. [codeSeperatorPos] must be provided with the position of the
   /// last executed CODESEPARATOR unless none have been executed in the script
   TaprootSignatureHasher({
     required this.tx,
     required this.inputN,
     required this.prevOuts,
-    required this.hashType,
+    this.hashType,
     this.leafHash,
     this.codeSeperatorPos = 0xFFFFFFFF,
   }) : txHashes = TransactionSignatureHashes(tx),
   prevOutHashes = PrevOutSignatureHashes(prevOuts) {
 
     SignatureHasher.checkInputN(tx, inputN);
 
-    if (hashType.single && inputN >= tx.outputs.length) {
+    if (hashType != null && hashType!.single && inputN >= tx.outputs.length) {
       throw ArgumentError.value(
         inputN, "inputN", "has no corresponing output for SIGHASH_SINGLE",
       );
@@ -61,29 +62,29 @@ final class TaprootSignatureHasher with Writable implements SignatureHasher {
     final extFlag = leafHash == null ? 0 : 1;
 
     writer.writeUInt8(0); // "Epoch"
-    writer.writeUInt8(
-      (hashType.all && !hashType.anyOneCanPay) ? 0 : hashType.value,
-    );
+    writer.writeUInt8(hashType == null ? 0 : hashType!.value);
+
+    final actualHashType = hashType ?? SigHashType.all();
 
     // Total transaction data
     writer.writeUInt32(tx.version);
     writer.writeUInt32(tx.locktime);
 
-    if (!hashType.anyOneCanPay) {
+    if (!actualHashType.anyOneCanPay) {
       writer.writeSlice(txHashes.prevouts.singleHash);
       writer.writeSlice(prevOutHashes!.amounts.singleHash);
       writer.writeSlice(prevOutHashes!.scripts.singleHash);
       writer.writeSlice(txHashes.sequences.singleHash);
     }
 
-    if (hashType.all) {
+    if (actualHashType.all) {
       writer.writeSlice(txHashes.outputs.singleHash);
     }
 
     // Data specific to spending input
     writer.writeUInt8(extFlag << 1);
 
-    if (hashType.anyOneCanPay) {
+    if (actualHashType.anyOneCanPay) {
       tx.inputs[inputN].prevOut.write(writer);
       prevOuts[inputN].write(writer);
       writer.writeUInt32(tx.inputs[inputN].sequence);
@@ -92,7 +93,7 @@ final class TaprootSignatureHasher with Writable implements SignatureHasher {
     }
 
     // Data specific to matched output
-    if (hashType.single) {
+    if (actualHashType.single) {
       writer.writeSlice(
         PrecomputeHasher.singleOutput(tx.outputs[inputN]).singleHash,
       );

diff --git a/coinlib/test/tx/sighash/taproot_signature_hasher_test.dart b/coinlib/test/tx/sighash/taproot_signature_hasher_test.dart
@@ -45,7 +45,7 @@ final prevOuts = [
 
 class TaprootSignatureVector {
   final int inputN;
-  final SigHashType hashType;
+  final SigHashType? hashType;
   final String? leafHashHex;
   final String sigHashHex;
   TaprootSignatureVector({
@@ -68,8 +68,13 @@ final taprootSigVectors = [
     sigHashHex: "325a644af47e8a5a2591cda0ab0723978537318f10e6a63d4eed783b96a71a4d",
   ),
   TaprootSignatureVector(
-    inputN: 4,
+    inputN: 3,
     hashType: SigHashType.all(),
+    sigHashHex: "bf013ea93474aa67815b1b6cc441d23b64fa310911d991e713cd34c7f5d46669",
+  ),
+  TaprootSignatureVector(
+    inputN: 4,
+    hashType: null,
     sigHashHex: "4f900a0bae3f1446fd48490c2958b5a023228f01661cda3496a11da502a7f7ef",
   ),
   TaprootSignatureVector(