def transaction_digest(tx_ins: list, tx_outs: list, lock_time: bytes = LOCK_TIME, sighash: int = SIGHASH_ALL) -> list:
"""Returns the digest of unsigned transaction according to SIGHASH"""
# BIP-143 https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki
# 1. nVersion of the transaction (4-byte little endian)
# 2. hashPrevouts (32-byte hash)
# 3. hashSequence (32-byte hash)
# 4. outpoint (32-byte hash + 4-byte little endian)
# 5. scriptCode of the input (serialized as scripts inside CTxOuts)
# 6. value of the output spent by this input (8-byte little endian)
# 7. nSequence of the input (4-byte little endian)
# 8. hashOutputs (32-byte hash)
# 9. nLocktime of the transaction (4-byte little endian)
# 10. sighash type of the signature (4-byte little endian)
if sighash == SIGHASH_ALL:
hash_prevouts = double_sha256(b''.join([tx_in.txid + tx_in.index for tx_in in tx_ins]))
hash_sequence = double_sha256(b''.join([tx_in.sequence for tx_in in tx_ins]))
hash_outputs = double_sha256(serialize_outputs(tx_outs))
digests = []
for tx_in in tx_ins:
digests.append(
VERSION +
hash_prevouts + hash_sequence +
tx_in.txid + tx_in.index + tx_in.locking_script_len + tx_in.locking_script + tx_in.satoshi + tx_in.sequence +
hash_outputs +
lock_time +
sighash.to_bytes(4, byteorder='little')
)
return digests
raise ValueError(f'Unsupported SIGHASH value {sighash}')
def create_p2pkh_transaction(utxosets, outputs, custom_pushdata=False):
version = VERSION_1
lock_time = LOCK_TIME
# sequence = SEQUENCE
hash_type = HASH_TYPE
unspents = [Unspent.from_dict(utxo) for utxo in utxosets]
input_count = int_to_varint(len(unspents))
output_count = int_to_varint(len(outputs))
output_block = construct_output_block(outputs,
custom_pushdata=custom_pushdata)
# Optimize for speed, not memory, by pre-computing values.
inputs = []
for unspent in unspents:
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('', 0, 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):
private_key = bsv(wif=utxosets[i]['PrivateKey'])
public_key = bytes.fromhex(private_key.public_key)
public_key_len = len(public_key).to_bytes(1, byteorder='little')
scriptCode = (OP_DUP + OP_HASH160 + OP_PUSH_20 +
address_to_public_key_hash(private_key.address) +
OP_EQUALVERIFY + OP_CHECKSIG)
scriptCode_len = int_to_varint(len(scriptCode))
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 SV
# 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_varint(len(script_sig))
return bytes_to_hex(version + input_count + construct_input_block(inputs) +
output_count + output_block + lock_time)
def b58c_encode(data, version=b'\x00'):
"""Converts bytes data into a base 58 check string.
WTF is Base 58 Check encoding? See here:
https://en.bitcoin.it/wiki/Base58Check_encoding
"""
data = version + data
data_without_zeros = data.lstrip(b'\x00')
nb_zeros = len(data) - len(data_without_zeros)
double_hash = double_sha256(data)
data = data + double_hash[0:4]
number = bytes_to_int(data)
b58 = int_to_base(number, B58)
return (b'1' * nb_zeros) + b58
# Verify the ECDSA signature of a signed transaction
# 4674da699de44c9c5d182870207ba89e5ccf395e5101dab6b0900bbf2f3b16cb
#
tx_inputs = inputs[0:1]
tx_outputs = [TxOut(address='1JDZRGf5fPjGTpqLNwjHFFZnagcZbwDsxw', satoshi=800)]
tx_digest = transaction_digest(tx_inputs, tx_outputs)[0]
serialized_sig = unhexlify('304402207e2c6eb8c4b20e251a71c580373a2836e209c50726e5f8b0f4f59f8af00eee1a022019ae1690e2eb4455add6ca5b86695d65d3261d914bc1d7abb40b188c7f46c9a5')
sig = deserialize_signature(serialized_sig)
print(verify_signature(pub_key, tx_digest, sig))
#
# Sign an unsigned transaction then broadcast
# c04bbd007ad3987f9b2ea8534175b5e436e43d64471bf32139b5851adf9f477e
#
serialized_pub_key = serialize_public_key(pub_key)
tx_inputs = inputs[1:]
tx_outputs = [TxOut(address='18CgRLx9hFZqDZv75J5kED7ANnDriwvpi1', satoshi=1700)]
tx_digests = transaction_digest(tx_inputs, tx_outputs)
for i in range(len(tx_digests)):
tx_digest = tx_digests[i]
sig = sign(priv_key, tx_digest)
serialized_sig = serialize_signature(sig)
# unlocking_script = LEN + der + sighash + LEN + public_key
tx_inputs[i].unlocking_script = bytes([len(serialized_sig) + 1]) + serialized_sig + bytes([SIGHASH_ALL, len(serialized_pub_key)]) + serialized_pub_key
print(hexlify(tx_inputs[i].unlocking_script))
tx_inputs[i].unlocking_script_len = int_to_varint(len(tx_inputs[i].unlocking_script))
print(hexlify(tx_inputs[i].unlocking_script_len))
raw = serialize_transaction(tx_inputs, tx_outputs)
print(hexlify(raw))
tx_id = double_sha256(raw)[::-1]
print(hexlify(tx_id))
def calc_txid(tx_hex):
return bytes_to_hex(double_sha256(hex_to_bytes(tx_hex))[::-1])
def generate_sighash_single_rawtx(utxosets, changeaddress, authrized_amount):
unspents = [Unspent.from_dict(utxo) for utxo in utxosets]
version = VERSION_1
lock_time = LOCK_TIME
#sequence = SEQUENCE
input_count = int_to_varint(len(unspents))
inputs = []
total_input_amount = 0
for unspent in unspents:
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('', 0, txid, txindex, amount))
total_input_amount += unspent.amount #satoshi
output_count = int_to_varint(1)
output_block = b''
output_script = (OP_DUP + OP_HASH160 + OP_PUSH_20 +
address_to_public_key_hash(changeaddress) +
OP_EQUALVERIFY + OP_CHECKSIG)
output_block += (total_input_amount - authrized_amount).to_bytes(
8, byteorder='little') #satoshi
output_block += int_to_varint(len(output_script))
output_block += output_script
hashPrevouts = double_sha256(b''.join([i.txid + i.txindex
for i in inputs]))
hashSequence = bytes.fromhex(
'0000000000000000000000000000000000000000000000000000000000000000')
# scriptCode_len is part of the script.
for i, txin in enumerate(inputs):
if i == 0:
hashOutputs = double_sha256(output_block)
hash_type = 0x43.to_bytes(4, byteorder='little') #sighash single
else:
hashOutputs = bytes.fromhex(
'0000000000000000000000000000000000000000000000000000000000000000'
)
hash_type = 0x42.to_bytes(4, byteorder='little') #sighash none
private_key = bsv(utxosets[i]['PrivateKey'])
public_key = bytes.fromhex(private_key.public_key)
public_key_len = len(public_key).to_bytes(1, byteorder='little')
scriptCode = (OP_DUP + OP_HASH160 + OP_PUSH_20 +
address_to_public_key_hash(private_key.address) +
OP_EQUALVERIFY + OP_CHECKSIG)
scriptCode_len = int_to_varint(len(scriptCode))
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 SV
# signature = private_key.sign(hashed) + b'\x01' sighash ALL ; single b'\x03' ,NONE b'\x02'
if i == 0:
signature = private_key.sign(hashed) + b'\x43'
else:
signature = private_key.sign(hashed) + b'\x42'
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_varint(len(script_sig))
return {
"version": bytes_to_hex(version),
"input": bytes_to_hex(input_count + construct_input_block(inputs)),
"output": bytes_to_hex(output_block),
"lock_time": bytes_to_hex(lock_time)
}
def hash_to_int(message: bytes) -> int:
"""Calculate the bitcoin double-sha256 hash of the message, return as an integer"""
h = double_sha256(message)
return int.from_bytes(h, byteorder='big')
