transaction: (move-only) move serialize_preimage to base class
This commit is contained in:
SomberNight
@@ -970,6 +970,100 @@ class Transaction:
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return b""
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raise UnknownTxinType("cannot construct scriptSig")
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def serialize_preimage(
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self,
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txin_index: int,
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*,
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sighash_cache: SighashCache = None,
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) -> bytes:
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nVersion = int.to_bytes(self.version, length=4, byteorder="little", signed=True)
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nLocktime = int.to_bytes(self.locktime, length=4, byteorder="little", signed=False)
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inputs = self.inputs()
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outputs = self.outputs()
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txin = inputs[txin_index]
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sighash = txin.sighash
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if sighash is None:
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sighash = Sighash.DEFAULT if txin.is_taproot() else Sighash.ALL
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if not Sighash.is_valid(sighash, is_taproot=txin.is_taproot()):
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raise Exception(f"SIGHASH_FLAG ({sighash}) not supported!")
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if sighash_cache is None:
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sighash_cache = SighashCache()
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if txin.is_segwit():
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if txin.is_taproot():
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scache = sighash_cache.get_witver1_data_for_tx(self)
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sighash_epoch = b"\x00"
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hash_type = int.to_bytes(sighash, length=1, byteorder="little", signed=False)
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# txdata
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preimage_txdata = bytearray()
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preimage_txdata += nVersion
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preimage_txdata += nLocktime
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if sighash & 0x80 != Sighash.ANYONECANPAY:
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preimage_txdata += scache.sha_prevouts
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preimage_txdata += scache.sha_amounts
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preimage_txdata += scache.sha_scriptpubkeys
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preimage_txdata += scache.sha_sequences
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if sighash & 3 not in (Sighash.NONE, Sighash.SINGLE):
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preimage_txdata += scache.sha_outputs
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# inputdata
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preimage_inputdata = bytearray()
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spend_type = bytes([0]) # (ext_flag * 2) + annex_present
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preimage_inputdata += spend_type
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if sighash & 0x80 == Sighash.ANYONECANPAY:
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preimage_inputdata += txin.prevout.serialize_to_network()
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preimage_inputdata += int.to_bytes(txin.value_sats(), length=8, byteorder="little", signed=False)
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preimage_inputdata += var_int(len(txin.scriptpubkey)) + txin.scriptpubkey
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preimage_inputdata += int.to_bytes(txin.nsequence, length=4, byteorder="little", signed=False)
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else:
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preimage_inputdata += int.to_bytes(txin_index, length=4, byteorder="little", signed=False)
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# TODO sha_annex
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# outputdata
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preimage_outputdata = bytearray()
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if sighash & 3 == Sighash.SINGLE:
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try:
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txout = outputs[txin_index]
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except IndexError:
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raise Exception("Using SIGHASH_SINGLE without a corresponding output") from None
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# note: we could cache this to avoid some potential DOS vectors:
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preimage_outputdata += sha256(txout.serialize_to_network())
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return bytes(sighash_epoch + hash_type + preimage_txdata + preimage_inputdata + preimage_outputdata)
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else: # segwit (witness v0)
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scache = sighash_cache.get_witver0_data_for_tx(self)
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if not (sighash & Sighash.ANYONECANPAY):
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hashPrevouts = scache.hashPrevouts
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else:
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hashPrevouts = bytes(32)
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if not (sighash & Sighash.ANYONECANPAY) and (sighash & 0x1f) != Sighash.SINGLE and (sighash & 0x1f) != Sighash.NONE:
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hashSequence = scache.hashSequence
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else:
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hashSequence = bytes(32)
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if (sighash & 0x1f) != Sighash.SINGLE and (sighash & 0x1f) != Sighash.NONE:
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hashOutputs = scache.hashOutputs
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elif (sighash & 0x1f) == Sighash.SINGLE and txin_index < len(outputs):
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# note: we could cache this to avoid some potential DOS vectors:
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hashOutputs = sha256d(outputs[txin_index].serialize_to_network())
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else:
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hashOutputs = bytes(32)
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outpoint = txin.prevout.serialize_to_network()
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preimage_script = self.get_preimage_script(txin)
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scriptCode = var_int(len(preimage_script)) + preimage_script
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amount = int.to_bytes(txin.value_sats(), length=8, byteorder="little", signed=False)
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nSequence = int.to_bytes(txin.nsequence, length=4, byteorder="little", signed=False)
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nHashType = int.to_bytes(sighash, length=4, byteorder="little", signed=False)
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preimage = nVersion + hashPrevouts + hashSequence + outpoint + scriptCode + amount + nSequence + hashOutputs + nLocktime + nHashType
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return preimage
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else: # legacy sighash (pre-segwit)
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if sighash != Sighash.ALL:
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raise Exception(f"SIGHASH_FLAG ({sighash}) not supported! (for legacy sighash)")
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preimage_script = self.get_preimage_script(txin)
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txins = var_int(len(inputs)) + b"".join(
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txin.serialize_to_network(script_sig=preimage_script if txin_index==k else b"")
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for k, txin in enumerate(inputs))
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txouts = var_int(len(outputs)) + b"".join(o.serialize_to_network() for o in outputs)
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nHashType = int.to_bytes(sighash, length=4, byteorder="little", signed=False)
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preimage = nVersion + txins + txouts + nLocktime + nHashType
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return preimage
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raise Exception("should not reach this")
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@classmethod
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def get_preimage_script(cls, txin: 'PartialTxInput') -> bytes:
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if txin.witness_script:
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@@ -2246,100 +2340,6 @@ class PartialTransaction(Transaction):
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self._outputs.sort(key = lambda o: (o.value, o.scriptpubkey))
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self.invalidate_ser_cache()
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def serialize_preimage(
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self,
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txin_index: int,
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*,
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sighash_cache: SighashCache = None,
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) -> bytes:
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nVersion = int.to_bytes(self.version, length=4, byteorder="little", signed=True)
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nLocktime = int.to_bytes(self.locktime, length=4, byteorder="little", signed=False)
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inputs = self.inputs()
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outputs = self.outputs()
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txin = inputs[txin_index]
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sighash = txin.sighash
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if sighash is None:
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sighash = Sighash.DEFAULT if txin.is_taproot() else Sighash.ALL
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if not Sighash.is_valid(sighash, is_taproot=txin.is_taproot()):
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raise Exception(f"SIGHASH_FLAG ({sighash}) not supported!")
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if sighash_cache is None:
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sighash_cache = SighashCache()
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if txin.is_segwit():
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if txin.is_taproot():
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scache = sighash_cache.get_witver1_data_for_tx(self)
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sighash_epoch = b"\x00"
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hash_type = int.to_bytes(sighash, length=1, byteorder="little", signed=False)
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# txdata
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preimage_txdata = bytearray()
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preimage_txdata += nVersion
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preimage_txdata += nLocktime
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if sighash & 0x80 != Sighash.ANYONECANPAY:
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preimage_txdata += scache.sha_prevouts
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preimage_txdata += scache.sha_amounts
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preimage_txdata += scache.sha_scriptpubkeys
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preimage_txdata += scache.sha_sequences
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if sighash & 3 not in (Sighash.NONE, Sighash.SINGLE):
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preimage_txdata += scache.sha_outputs
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# inputdata
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preimage_inputdata = bytearray()
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spend_type = bytes([0]) # (ext_flag * 2) + annex_present
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preimage_inputdata += spend_type
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if sighash & 0x80 == Sighash.ANYONECANPAY:
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preimage_inputdata += txin.prevout.serialize_to_network()
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preimage_inputdata += int.to_bytes(txin.value_sats(), length=8, byteorder="little", signed=False)
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preimage_inputdata += var_int(len(txin.scriptpubkey)) + txin.scriptpubkey
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preimage_inputdata += int.to_bytes(txin.nsequence, length=4, byteorder="little", signed=False)
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else:
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preimage_inputdata += int.to_bytes(txin_index, length=4, byteorder="little", signed=False)
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# TODO sha_annex
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# outputdata
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preimage_outputdata = bytearray()
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if sighash & 3 == Sighash.SINGLE:
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try:
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txout = outputs[txin_index]
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except IndexError:
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raise Exception("Using SIGHASH_SINGLE without a corresponding output") from None
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# note: we could cache this to avoid some potential DOS vectors:
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preimage_outputdata += sha256(txout.serialize_to_network())
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return bytes(sighash_epoch + hash_type + preimage_txdata + preimage_inputdata + preimage_outputdata)
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else: # segwit (witness v0)
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scache = sighash_cache.get_witver0_data_for_tx(self)
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if not (sighash & Sighash.ANYONECANPAY):
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hashPrevouts = scache.hashPrevouts
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else:
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hashPrevouts = bytes(32)
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if not (sighash & Sighash.ANYONECANPAY) and (sighash & 0x1f) != Sighash.SINGLE and (sighash & 0x1f) != Sighash.NONE:
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hashSequence = scache.hashSequence
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else:
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hashSequence = bytes(32)
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if (sighash & 0x1f) != Sighash.SINGLE and (sighash & 0x1f) != Sighash.NONE:
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hashOutputs = scache.hashOutputs
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elif (sighash & 0x1f) == Sighash.SINGLE and txin_index < len(outputs):
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# note: we could cache this to avoid some potential DOS vectors:
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hashOutputs = sha256d(outputs[txin_index].serialize_to_network())
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else:
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hashOutputs = bytes(32)
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outpoint = txin.prevout.serialize_to_network()
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preimage_script = self.get_preimage_script(txin)
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scriptCode = var_int(len(preimage_script)) + preimage_script
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amount = int.to_bytes(txin.value_sats(), length=8, byteorder="little", signed=False)
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nSequence = int.to_bytes(txin.nsequence, length=4, byteorder="little", signed=False)
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nHashType = int.to_bytes(sighash, length=4, byteorder="little", signed=False)
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preimage = nVersion + hashPrevouts + hashSequence + outpoint + scriptCode + amount + nSequence + hashOutputs + nLocktime + nHashType
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return preimage
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else: # legacy sighash (pre-segwit)
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if sighash != Sighash.ALL:
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raise Exception(f"SIGHASH_FLAG ({sighash}) not supported! (for legacy sighash)")
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preimage_script = self.get_preimage_script(txin)
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txins = var_int(len(inputs)) + b"".join(
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txin.serialize_to_network(script_sig=preimage_script if txin_index==k else b"")
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for k, txin in enumerate(inputs))
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txouts = var_int(len(outputs)) + b"".join(o.serialize_to_network() for o in outputs)
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nHashType = int.to_bytes(sighash, length=4, byteorder="little", signed=False)
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preimage = nVersion + txins + txouts + nLocktime + nHashType
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return preimage
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raise Exception("should not reach this")
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def sign(self, keypairs: Mapping[bytes, bytes]) -> None:
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# keypairs: pubkey_bytes -> secret_bytes
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sighash_cache = SighashCache()
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