def parse(cls: Type["Sig"],
data: BinaryData,
check_validity: bool = True) -> "Sig":
"""Return a Sig by parsing binary data.
Deserialize a strict ASN.1 DER representation of an ECDSA signature.
"""
stream = bytesio_from_binarydata(data)
ec = secp256k1
# [0x30] [data-size][0x02][r-size][r][0x02][s-size][s]
marker = stream.read(1)
if marker != _DER_SIG_MARKER:
err_msg = f"invalid compound header: {marker.hex()}"
err_msg += f", instead of DER sequence tag {_DER_SIG_MARKER.hex()}"
raise BTClibValueError(err_msg)
# [data-size][0x02][r-size][r][0x02][s-size][s]
sig_data = var_bytes.parse(stream, forbid_zero_size=True)
# [0x02][r-size][r][0x02][s-size][s]
sig_data_substream = bytesio_from_binarydata(sig_data)
r = _deserialize_scalar(sig_data_substream)
s = _deserialize_scalar(sig_data_substream)
# to prevent malleability
# the sig_data_substream must have been consumed entirely
if sig_data_substream.read(1) != b"":
err_msg = "invalid DER sequence length"
raise BTClibValueError(err_msg)
return cls(r, s, ec, check_validity)
def parse(cls: Type["Witness"],
data: BinaryData,
check_validity: bool = True) -> "Witness":
"Return a Witness by parsing binary data."
data = bytesio_from_binarydata(data)
n = var_int.parse(data)
stack = [var_bytes.parse(data) for _ in range(n)]
return cls(stack, check_validity)
def parse(cls: Type["TxOut"],
data: BinaryData,
check_validity: bool = True) -> "TxOut":
stream = bytesio_from_binarydata(data)
value = int.from_bytes(stream.read(8),
byteorder="little",
signed=False)
script = var_bytes.parse(stream)
return cls(value, ScriptPubKey(script, "mainnet"), check_validity)
def parse(cls: Type["TxIn"],
data: BinaryData,
check_validity: bool = True) -> "TxIn":
stream = bytesio_from_binarydata(data)
prev_out = OutPoint.parse(stream)
script_sig = var_bytes.parse(stream)
sequence = int.from_bytes(stream.read(4),
byteorder="little",
signed=False)
return cls(prev_out, script_sig, sequence, Witness(), check_validity)
def _deserialize_scalar(sig_data_stream: BytesIO) -> int:
marker = sig_data_stream.read(1)
if marker != _DER_SCALAR_MARKER:
err_msg = f"invalid value header: {marker.hex()}"
err_msg += f", instead of integer element {_DER_SCALAR_MARKER.hex()}"
raise BTClibValueError(err_msg)
r_bytes = var_bytes.parse(sig_data_stream, forbid_zero_size=True)
if r_bytes[0] == 0 and r_bytes[1] < 0x80:
raise BTClibValueError("invalid 'highest bit set' padding")
if r_bytes[0] >= 0x80:
raise BTClibValueError("invalid negative scalar")
return int.from_bytes(r_bytes, byteorder="big", signed=False)
def parse(
cls: Type["TxOut"],
data: BinaryData,
check_validity: bool = True,
) -> "TxOut":
stream = bytesio_from_binarydata(data)
value = int.from_bytes(stream.read(8),
byteorder="little",
signed=False)
script = var_bytes.parse(stream)
return cls(
value,
ScriptPubKey(script, "mainnet", check_validity=False
), # https://github.com/bitcoin/bitcoin/issues/320
check_validity,
)
def height(self) -> Optional[int]:
"""Return the height committed into a BIP34 coinbase script_sig.
Version 2 blocks commit block height into the coinbase script_sig.
https://github.com/bitcoin/bips/blob/master/bip-0034.mediawiki
Block 227,835 (2013-03-24 15:49:13 GMT) was the last version 1 block.
"""
if not self.transactions[0].is_coinbase():
raise BTClibValueError("first transaction is not a coinbase")
if self.header.version == 1:
return None
# Height is "serialized CScript": first byte is number of bytes,
# followed by the _signed_ little-endian representation of the height
# (genesis block is height zero).
coinbase_script = self.transactions[0].vin[0].script_sig
height_ = var_bytes.parse(coinbase_script)
return decode_num(height_)
def addresses(script_pub_key: Octets, network: str = "mainnet") -> List[str]:
"Return the p2pkh addresses of the pub_keys used in a p2ms script_pub_key."
script_pub_key = bytes_from_octets(script_pub_key)
# p2ms [m, pub_keys, n, OP_CHECKMULTISIG]
length = len(script_pub_key)
if length < 37:
raise BTClibValueError(f"invalid p2ms length {length}")
if script_pub_key[-1] != 0xAE:
raise BTClibValueError("missing final OP_CHECKMULTISIG")
m = script_pub_key[0] - 80
if not 0 < m < 17:
raise BTClibValueError(f"invalid m in m-of-n: {m}")
n = script_pub_key[-2] - 80
if not m <= n < 17:
raise BTClibValueError(f"invalid m-of-n: {m}-of-{n}")
stream = bytesio_from_binarydata(script_pub_key[1:-2])
pub_keys = [var_bytes.parse(stream) for _ in range(n)]
if stream.read(1):
raise BTClibValueError("invalid p2ms script_pub_key size")
return [b58.p2pkh(pub_key, network) for pub_key in pub_keys]
