psbt: add MuSig2 fields

Author: Sjors

hwilib/psbt.py

@@ -103,6 +103,9 @@ class PartiallySignedInput:
     PSBT_IN_TAP_BIP32_DERIVATION = 0x16
     PSBT_IN_TAP_INTERNAL_KEY = 0x17
     PSBT_IN_TAP_MERKLE_ROOT = 0x18
+    PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS = 0x1a
+    PSBT_IN_MUSIG2_PUB_NONCE = 0x1b
+    PSBT_IN_MUSIG2_PARTIAL_SIG = 0x1c
 
     def __init__(self, version: int) -> None:
         self.non_witness_utxo: Optional[CTransaction] = None
@@ -125,6 +128,9 @@ def __init__(self, version: int) -> None:
         self.tap_bip32_paths: Dict[bytes, Tuple[Set[bytes], KeyOriginInfo]] = {}
         self.tap_internal_key = b""
         self.tap_merkle_root = b""
+        self.musig2_participant_pubkeys = {}
+        self.musig2_pub_nonce = {}
+        self.musig2_partial_sig = {}
         self.unknown: Dict[bytes, bytes] = {}
 
         self.version: int = version
@@ -153,6 +159,9 @@ def set_null(self) -> None:
         self.sequence = None
         self.time_locktime = None
         self.height_locktime = None
+        self.musig2_participant_pubkeys.clear()
+        self.musig2_pub_nonce.clear()
+        self.musig2_partial_sig.clear()
         self.unknown.clear()
 
     def deserialize(self, f: Readable) -> None:
@@ -351,6 +360,18 @@ def deserialize(self, f: Readable) -> None:
                 self.tap_merkle_root = deser_string(f)
                 if len(self.tap_merkle_root) != 32:
                     raise PSBTSerializationError("Input Taproot merkle root is not 32 bytes")
+            elif key_type == PartiallySignedInput.PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS:
+                if key in key_lookup:
+                    raise PSBTSerializationError("Duplicate key, input MuSig2 Participant Public Keys already provided")
+                self.musig2_participant_pubkeys = deser_string(f)
+            elif key_type == PartiallySignedInput.PSBT_IN_MUSIG2_PUB_NONCE:
+                if key in key_lookup:
+                    raise PSBTSerializationError("Duplicate key, input MuSig2 Public Nonce already provided")
+                self.musig2_pub_nonce = deser_string(f)
+            elif key_type == PartiallySignedInput.PSBT_IN_MUSIG2_PARTIAL_SIG:
+                if key in key_lookup:
+                    raise PSBTSerializationError("Duplicate key, input MuSig2 Participant Partial Signature already provided")
+                self.musig2_partial_sig = deser_string(f)
             else:
                 if key in self.unknown:
                     raise PSBTSerializationError("Duplicate key, key for unknown value already provided")
@@ -441,6 +462,18 @@ def serialize(self) -> bytes:
             witstack = self.final_script_witness.serialize()
             r += ser_string(witstack)
 
+        if len(self.musig2_participant_pubkeys) != 0:
+            r += ser_string(ser_compact_size(PartiallySignedInput.PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS))
+            r += ser_string(self.musig2_participant_pubkeys)
+
+        if len(self.musig2_pub_nonce) != 0:
+            r += ser_string(ser_compact_size(PartiallySignedInput.PSBT_IN_MUSIG2_PUB_NONCE))
+            r += ser_string(self.musig2_pub_nonce)
+
+        if len(self.musig2_partial_sig) != 0:
+            r += ser_string(ser_compact_size(PartiallySignedInput.PSBT_IN_MUSIG2_PARTIAL_SIG))
+            r += ser_string(self.musig2_partial_sig)
+
         if self.version >= 2:
             if len(self.prev_txid) != 0:
                 r += ser_string(ser_compact_size(PartiallySignedInput.PSBT_IN_PREVIOUS_TXID))
@@ -483,6 +516,7 @@ class PartiallySignedOutput:
     PSBT_OUT_TAP_INTERNAL_KEY = 0x05
     PSBT_OUT_TAP_TREE = 0x06
     PSBT_OUT_TAP_BIP32_DERIVATION = 0x07
+    PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS = 0x08
 
     def __init__(self, version: int) -> None:
         self.redeem_script = b""
@@ -493,6 +527,7 @@ def __init__(self, version: int) -> None:
         self.tap_internal_key = b""
         self.tap_tree = b""
         self.tap_bip32_paths: Dict[bytes, Tuple[Set[bytes], KeyOriginInfo]] = {}
+        self.musig2_participant_pubkeys = {}
         self.unknown: Dict[bytes, bytes] = {}
 
         self.version: int = version
@@ -509,6 +544,7 @@ def set_null(self) -> None:
         self.tap_bip32_paths.clear()
         self.amount = None
         self.script = b""
+        self.musig2_participant_pubkeys = {}
         self.unknown.clear()
 
     def deserialize(self, f: Readable) -> None:
@@ -589,6 +625,10 @@ def deserialize(self, f: Readable) -> None:
                 for i in range(0, num_hashes):
                     leaf_hashes.add(vs.read(32))
                 self.tap_bip32_paths[xonly] = (leaf_hashes, KeyOriginInfo.deserialize(vs.read()))
+            elif key_type == PartiallySignedOutput.PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS:
+                if key in key_lookup:
+                    raise PSBTSerializationError("Duplicate key, output MuSig2 Participant Public Keys already provided")
+                self.musig2_participant_pubkeys = deser_string(f)
             else:
                 if key in self.unknown:
                     raise PSBTSerializationError("Duplicate key, key for unknown value already provided")
@@ -646,6 +686,10 @@ def serialize(self) -> bytes:
             value += origin.serialize()
             r += ser_string(value)
 
+        if len(self.musig2_participant_pubkeys) != 0:
+            r += ser_string(ser_compact_size(PartiallySignedOutput.PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS))
+            r += ser_string(self.musig2_participant_pubkeys)
+
         for key, value in sorted(self.unknown.items()):
             r += ser_string(key)
             r += ser_string(value)