def verify_input(self, input_index):
# '''Returns whether the input has a valid signature'''
# get the relevant input
tx_in = self.tx_ins[input_index]
# grab the previous ScriptPubKey
script_pubkey = tx_in.script_pubkey(testnet=self.testnet)
# check to see if the ScriptPubkey is a p2sh
if script_pubkey.is_p2sh_script_pubkey():
# the last cmd has to be the RedeemScript to trigger
cmd = tx_in.script_sig.cmds[-1]
# parse the RedeemScript
raw_redeem = int_to_little_endian(len(cmd), 1) + cmd
redeem_script = Script.parse(BytesIO(raw_redeem))
# the RedeemScript might be p2wpkh or p2wsh
if redeem_script.is_p2wpkh_script_pubkey():
z = self.sig_hash_bip143(input_index, redeem_script)
witness = tx_in.witness
elif redeem_script.is_p2wsh_script_pubkey():
cmd = tx_in.witness[-1]
raw_witness = encode_varint(len(cmd)) + cmd
witness_script = Script.parse(BytesIO(raw_witness))
z = self.sig_hash_bip143(input_index,
witness_script=witness_script)
witness = tx_in.witness
else:
z = self.sig_hash(input_index, redeem_script)
witness = None
else:
# ScriptPubkey might be a p2wpkh or p2wsh
if script_pubkey.is_p2wpkh_script_pubkey():
z = self.sig_hash_bip143(input_index)
witness = tx_in.witness
elif script_pubkey.is_p2wsh_script_pubkey():
cmd = tx_in.witness[-1]
raw_witness = encode_varint(len(cmd)) + cmd
witness_script = Script.parse(BytesIO(raw_witness))
z = self.sig_hash_bip143(input_index,
witness_script=witness_script)
witness = tx_in.witness
else:
z = self.sig_hash(input_index)
witness = None
# combine the current ScriptSig and the previous ScriptPubKey
combined = tx_in.script_sig + script_pubkey
# evaluate the combined script
return combined.evaluate(z, witness)
def parse(cls, s):
#Takes a byte stream and parses the tx_output at the start
#return a TxOut object
# amount is an integer in 8 bytes, little endian
amount = little_endian_to_int(s.read(8))
# use Script.parse to get the ScriptPubKey
script_pubkey = Script.parse(s)
# return an instance of the class (see __init__ for args)
return cls(amount, script_pubkey)
def parse(cls, s):
# Takes a byte stream and parses the tx_input at the start. return a TxIn object
# prev_tx is 32 bytes, little endian
prev_tx = s.read(32)[::-1]
# prev_index is an integer in 4 bytes, little endian
prev_index = little_endian_to_int(s.read(4))
# use Script.parse to get the ScriptSig
script_sig = Script.parse(s)
# sequence is an integer in 4 bytes, little-endian
sequence = little_endian_to_int(s.read(4))
# return an instance of the class (see __init__ for args)
return cls(prev_tx, prev_index, script_sig, sequence)
def parse(cls, s):
'''Takes a byte stream and parses the tx_input at the start
return a TxIn object
'''
# prev_tx is 32 bytes, little endian
# prev_index is an integer in 4 bytes, little endian
# use Script.parse to get the ScriptSig
# sequence is an integer in 4 bytes, little-endian
# return an instance of the class (see __init__ for args)
# raise NotImplementedError
prev_tx = s.read(32)[::-1]
prev_index = little_endian_to_int(s.read(4))
script_sig = Script.parse(s)
sequence = little_endian_to_int(s.read(4))
return cls(prev_tx, prev_index, script_sig, sequence)
