Add p2sh

src/script.py

@@ -430,12 +430,12 @@ def op_checkmultisig(self) -> int:
         # 3. Handle proper error cases
 
         verified = True  # Replace with actual verification
-        
+
         self.stack.push(b'\x01' if verified else b'\x00')
         return 1
 
     @staticmethod
-    def combine_scripts(*scripts: Union[bytes, 'Script'], json_transaction: dict) -> 'Script':
+    def combine_scripts(*scripts: Union[bytes, 'Script'], json_transaction: dict, segwit: bool = False) -> 'Script':
         """
         Combine multiple scripts into a single script.
         Accepts both bytes and Script objects.
@@ -448,5 +448,5 @@ def combine_scripts(*scripts: Union[bytes, 'Script'], json_transaction: dict) ->
                 combined.extend(script)
             else:
                 raise InvalidScriptException(f"Invalid script type: {type(script)}")
-        return Script(bytes(combined), json_transaction)
+        return Script(bytes(combined), json_transaction, segwit=segwit)
 

src/transaction.py

@@ -2,12 +2,14 @@
 import json
 
 from ecdsa import VerifyingKey, SECP256k1, BadSignatureError
+from Crypto.Hash import RIPEMD160
 
 from src.script import Script, InvalidScriptException
 from src.serialize import serialize_transaction
 from src.utils import decode_hex, get_filename_without_extension, hash160
 from src.verify import parse_der_signature_bytes, valid_transaction_syntax
 
+
 def calculate_txid(transaction_content, coinbase=False):
     # Serialize the transaction content
     if coinbase:
@@ -104,13 +106,14 @@ def valid_input(self, vin_idx, vin):
         if scriptpubkey_type == "p2pkh":
             return self.validate_p2pkh(vin_idx, vin)
         elif scriptpubkey_type == "p2sh":
-            pass
+            return self.validate_p2sh(vin_idx, vin)
         elif scriptpubkey_type == "v0_p2wsh":
             pass
         elif scriptpubkey_type == "v1_p2tr":
             pass
         elif scriptpubkey_type == "v0_p2wpkh":
-            return self.validate_p2wpkh(vin_idx, vin)
+            #return self.validate_p2wpkh(vin_idx, vin)
+            pass
 
         # Unknown script type.
         return False        
@@ -139,6 +142,49 @@ def validate_p2pkh(self, vin_idx, vin):
 
         return is_valid
 
+    def validate_p2sh(self, vin_idx, vin):
+        #################
+        # Pubkey script #
+        #################
+        scriptsig = decode_hex(vin.get("scriptsig", ""))
+        if not scriptsig:
+            return False
+        prevout = vin.get("prevout", {})
+        if not prevout:
+            return False
+        scriptpubkey = decode_hex(prevout.get("scriptpubkey", ""))
+
+        # Check if the scriptpubkey is a P2SH script
+        if scriptpubkey[:2] != b'\xa9\x14' or scriptpubkey[-1:] != b'\x87':
+            # Not a P2SH script, fallback to P2PKH validation
+            return self.validate_p2pkh(vin_idx, vin)
+
+        # Extract the script hash from the scriptpubkey        
+        script_hash = scriptpubkey[2:-1]
+
+        # Find the redeem script in the scriptsig
+        redeem_script_len = int.from_bytes(scriptsig[0:1], byteorder='little')
+        redeem_script = scriptsig[1:1+redeem_script_len]
+
+        # Create the combined script
+        script = Script.combine_scripts(redeem_script, json_transaction=self.json_transaction)
+
+        # Hash the redeem script and compare with the script hash
+        # Compute the HASH160 (RIPEMD-160 of SHA-256) of the redeem script
+        sha256_hash = hashlib.sha256(redeem_script).digest()
+        ripemd160 = RIPEMD160.new()
+        ripemd160.update(sha256_hash)
+        computed_script_hash = ripemd160.digest()
+
+        # Compare with the provided script hash
+        if computed_script_hash != script_hash:            
+            return False
+
+        # Execute the redeem script
+        is_valid = script.execute()
+
+        return is_valid
+
     def validate_p2wpkh(self, vin_idx, vin):
         """
         Validate a Pay-to-Witness-Public-Key-Hash (P2WPKH) transaction input
@@ -200,6 +246,7 @@ def validate_p2wpkh(self, vin_idx, vin):
 
         # Execute the script
         try:
+            #return script.execute()
             return script.execute()
         except Exception as e:
             print(f"P2WPKH validation error: {str(e)}")