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 calc_txid(tx_hex):
return bytes_to_hex(double_sha256(hex_to_bytes(tx_hex))[::-1])
def test_construct_input_block():
assert construct_input_block(INPUTS) == hex_to_bytes(INPUT_BLOCK)
def test_pushdata_message(self):
BYTES = len(b'hello').to_bytes(1, byteorder='little') + b'hello'
assert construct_output_block(OUTPUTS + [(BYTES, 0)],
custom_pushdata=True) == hex_to_bytes(
OUTPUT_BLOCK_MESSAGE_PUSHDATA)
def test_message(self):
assert construct_output_block(OUTPUTS + MESSAGES) == hex_to_bytes(
OUTPUT_BLOCK_MESSAGES)
def test_no_message(self):
assert construct_output_block(OUTPUTS) == hex_to_bytes(OUTPUT_BLOCK)
def test_hex_to_bytes():
assert hex_to_bytes(HEX) == BYTES_BIG
assert hex_to_bytes(ODD_HEX) == ODD_HEX_BYTES