def create_p2pkh_transaction(private_key,
unspents,
outputs,
custom_pushdata=False):
public_key = private_key.public_key
public_key_len = len(public_key).to_bytes(1, byteorder="little")
scriptCode = private_key.scriptcode
scriptCode_len = int_to_varint(len(scriptCode))
version = VERSION_1
lock_time = LOCK_TIME
# sequence = SEQUENCE
hash_type = HASH_TYPE
input_count = int_to_unknown_bytes(len(unspents), byteorder="little")
output_count = int_to_unknown_bytes(len(outputs), byteorder="little")
output_block = construct_output_block(outputs,
custom_pushdata=custom_pushdata)
# Optimize for speed, not memory, by pre-computing values.
inputs = []
for unspent in unspents:
script = hex_to_bytes(unspent.script)
script_len = int_to_unknown_bytes(len(script), byteorder="little")
txid = hex_to_bytes(unspent.txid)[::-1]
txindex = unspent.txindex.to_bytes(4, byteorder="little")
amount = unspent.amount.to_bytes(8, byteorder="little")
inputs.append(TxIn(script, script_len, txid, txindex, amount))
hashPrevouts = double_sha256(b"".join([i.txid + i.txindex
for i in inputs]))
hashSequence = double_sha256(b"".join([SEQUENCE for i in inputs]))
hashOutputs = double_sha256(output_block)
# scriptCode_len is part of the script.
for i, txin in enumerate(inputs):
to_be_hashed = (version + hashPrevouts + hashSequence + txin.txid +
txin.txindex + scriptCode_len + scriptCode +
txin.amount + SEQUENCE + hashOutputs + lock_time +
hash_type)
hashed = sha256(to_be_hashed) # BIP-143: Used for Bitcoin Cash
# signature = private_key.sign(hashed) + b'\x01'
signature = private_key.sign(hashed) + b"\x41"
script_sig = (len(signature).to_bytes(1, byteorder="little") +
signature + public_key_len + public_key)
inputs[i].script = script_sig
inputs[i].script_len = int_to_unknown_bytes(len(script_sig),
byteorder="little")
return bytes_to_hex(version + input_count + construct_input_block(inputs) +
output_count + output_block + lock_time)
def _tx_in_boilerplate(unspent, output, script_code, construct_output_block_f):
script = hex_to_bytes(unspent.script)
script_len = int_to_unknown_bytes(len(script), byteorder='little')
tx_id = hex_to_bytes(unspent.txid)[::-1]
tx_index = unspent.txindex.to_bytes(4, byteorder='little')
amount = unspent.amount.to_bytes(8, byteorder='little')
tx_in = TxIn(script, script_len, tx_id, tx_index, amount)
hash_previous_outputs = double_sha256(tx_id + tx_index)
hash_sequence = double_sha256(SEQUENCE)
output_block = construct_output_block_f([output])
hash_outputs = double_sha256(output_block)
to_be_hashed = (VERSION_1 + hash_previous_outputs + hash_sequence +
tx_in.txid + tx_in.txindex +
int_to_varint(len(script_code)) + script_code +
tx_in.amount + SEQUENCE + hash_outputs + LOCK_TIME +
HASH_TYPE)
hashed = sha256(to_be_hashed) # BIP-143: Used for Bitcoin Cash
return tx_in, hashed, output_block
def calc_txid(tx_hex):
return bytes_to_hex(double_sha256(hex_to_bytes(tx_hex))[::-1])