#!/usr/bin/env python3
# Copyright (c) 2015-2022 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""Functionality to build scripts, as well as signature hash functions.
This file is modified from python-bitcoinlib.
"""
from collections import namedtuple
import unittest
from .key import TaggedHash, tweak_add_pubkey, compute_xonly_pubkey
from .messages import (
CTransaction,
CTxOut,
hash256,
ser_string,
ser_uint256,
sha256,
uint256_from_str,
)
from .crypto.ripemd160 import ripemd160
MAX_SCRIPT_ELEMENT_SIZE = 520
MAX_PUBKEYS_PER_MULTI_A = 999
LOCKTIME_THRESHOLD = 500000000
ANNEX_TAG = 0x50
LEAF_VERSION_TAPSCRIPT = 0xc0
def hash160(s):
return ripemd160(sha256(s))
def bn2vch(v):
"""Convert number to bitcoin-specific little endian format."""
# We need v.bit_length() bits, plus a sign bit for every nonzero number.
n_bits = v.bit_length() + (v != 0)
# The number of bytes for that is:
n_bytes = (n_bits + 7) // 8
# Convert number to absolute value + sign in top bit.
encoded_v = 0 if v == 0 else abs(v) | ((v < 0) << (n_bytes * 8 - 1))
# Serialize to bytes
return encoded_v.to_bytes(n_bytes, 'little')
class CScriptOp(int):
"""A single script opcode"""
__slots__ = ()
@staticmethod
def encode_op_pushdata(d):
"""Encode a PUSHDATA op, returning bytes"""
if len(d) < 0x4c:
return b'' + bytes([len(d)]) + d # OP_PUSHDATA
elif len(d) <= 0xff:
return b'\x4c' + bytes([len(d)]) + d # OP_PUSHDATA1
elif len(d) <= 0xffff:
return b'\x4d' + len(d).to_bytes(2, "little") + d # OP_PUSHDATA2
elif len(d) <= 0xffffffff:
return b'\x4e' + len(d).to_bytes(4, "little") + d # OP_PUSHDATA4
else:
raise ValueError("Data too long to encode in a PUSHDATA op")
@staticmethod
def encode_op_n(n):
"""Encode a small integer op, returning an opcode"""
if not (0 <= n <= 16):
raise ValueError('Integer must be in range 0 <= n <= 16, got %d' % n)
if n == 0:
return OP_0
else:
return CScriptOp(OP_1 + n - 1)
def decode_op_n(self):
"""Decode a small integer opcode, returning an integer"""
if self == OP_0:
return 0
if not (self == OP_0 or OP_1 <= self <= OP_16):
raise ValueError('op %r is not an OP_N' % self)
return int(self - OP_1 + 1)
def is_small_int(self):
"""Return true if the op pushes a small integer to the stack"""
if 0x51 <= self <= 0x60 or self == 0:
return True
else:
return False
def __str__(self):
return repr(self)
def __repr__(self):
if self in OPCODE_NAMES:
return OPCODE_NAMES[self]
else:
return 'CScriptOp(0x%x)' % self
def __new__(cls, n):
try:
return _opcode_instances[n]
except IndexError:
assert len(_opcode_instances) == n
_opcode_instances.append(super().__new__(cls, n))
return _opcode_instances[n]
OPCODE_NAMES: dict[CScriptOp, str] = {}
_opcode_instances: list[CScriptOp] = []
# Populate opcode instance table
for n in range(0xff + 1):
CScriptOp(n)
# push value
OP_0 = CScriptOp(0x00)
OP_FALSE = OP_0
OP_PUSHDATA1 = CScriptOp(0x4c)
OP_PUSHDATA2 = CScriptOp(0x4d)
OP_PUSHDATA4 = CScriptOp(0x4e)
OP_1NEGATE = CScriptOp(0x4f)
OP_RESERVED = CScriptOp(0x50)
OP_1 = CScriptOp(0x51)
OP_TRUE = OP_1
OP_2 = CScriptOp(0x52)
OP_3 = CScriptOp(0x53)
OP_4 = CScriptOp(0x54)
OP_5 = CScriptOp(0x55)
OP_6 = CScriptOp(0x56)
OP_7 = CScriptOp(0x57)
OP_8 = CScriptOp(0x58)
OP_9 = CScriptOp(0x59)
OP_10 = CScriptOp(0x5a)
OP_11 = CScriptOp(0x5b)
OP_12 = CScriptOp(0x5c)
OP_13 = CScriptOp(0x5d)
OP_14 = CScriptOp(0x5e)
OP_15 = CScriptOp(0x5f)
OP_16 = CScriptOp(0x60)
# control
OP_NOP = CScriptOp(0x61)
OP_VER = CScriptOp(0x62)
OP_IF = CScriptOp(0x63)
OP_NOTIF = CScriptOp(0x64)
OP_VERIF = CScriptOp(0x65)
OP_VERNOTIF = CScriptOp(0x66)
OP_ELSE = CScriptOp(0x67)
OP_ENDIF = CScriptOp(0x68)
OP_VERIFY = CScriptOp(0x69)
OP_RETURN = CScriptOp(0x6a)
# stack ops
OP_TOALTSTACK = CScriptOp(0x6b)
OP_FROMALTSTACK = CScriptOp(0x6c)
OP_2DROP = CScriptOp(0x6d)
OP_2DUP = CScriptOp(0x6e)
OP_3DUP = CScriptOp(0x6f)
OP_2OVER = CScriptOp(0x70)
OP_2ROT = CScriptOp(0x71)
OP_2SWAP = CScriptOp(0x72)
OP_IFDUP = CScriptOp(0x73)
OP_DEPTH = CScriptOp(0x74)
OP_DROP = CScriptOp(0x75)
OP_DUP = CScriptOp(0x76)
OP_NIP = CScriptOp(0x77)
OP_OVER = CScriptOp(0x78)
OP_PICK = CScriptOp(0x79)
OP_ROLL = CScriptOp(0x7a)
OP_ROT = CScriptOp(0x7b)
OP_SWAP = CScriptOp(0x7c)
OP_TUCK = CScriptOp(0x7d)
# splice ops
OP_CAT = CScriptOp(0x7e)
OP_SUBSTR = CScriptOp(0x7f)
OP_LEFT = CScriptOp(0x80)
OP_RIGHT = CScriptOp(0x81)
OP_SIZE = CScriptOp(0x82)
# bit logic
OP_INVERT = CScriptOp(0x83)
OP_AND = CScriptOp(0x84)
OP_OR = CScriptOp(0x85)
OP_XOR = CScriptOp(0x86)
OP_EQUAL = CScriptOp(0x87)
OP_EQUALVERIFY = CScriptOp(0x88)
OP_RESERVED1 = CScriptOp(0x89)
OP_RESERVED2 = CScriptOp(0x8a)
# numeric
OP_1ADD = CScriptOp(0x8b)
OP_1SUB = CScriptOp(0x8c)
OP_2MUL = CScriptOp(0x8d)
OP_2DIV = CScriptOp(0x8e)
OP_NEGATE = CScriptOp(0x8f)
OP_ABS = CScriptOp(0x90)
OP_NOT = CScriptOp(0x91)
OP_0NOTEQUAL = CScriptOp(0x92)
OP_ADD = CScriptOp(0x93)
OP_SUB = CScriptOp(0x94)
OP_MUL = CScriptOp(0x95)
OP_DIV = CScriptOp(0x96)
OP_MOD = CScriptOp(0x97)
OP_LSHIFT = CScriptOp(0x98)
OP_RSHIFT = CScriptOp(0x99)
OP_BOOLAND = CScriptOp(0x9a)
OP_BOOLOR = CScriptOp(0x9b)
OP_NUMEQUAL = CScriptOp(0x9c)
OP_NUMEQUALVERIFY = CScriptOp(0x9d)
OP_NUMNOTEQUAL = CScriptOp(0x9e)
OP_LESSTHAN = CScriptOp(0x9f)
OP_GREATERTHAN = CScriptOp(0xa0)
OP_LESSTHANOREQUAL = CScriptOp(0xa1)
OP_GREATERTHANOREQUAL = CScriptOp(0xa2)
OP_MIN = CScriptOp(0xa3)
OP_MAX = CScriptOp(0xa4)
OP_WITHIN = CScriptOp(0xa5)
# crypto
OP_RIPEMD160 = CScriptOp(0xa6)
OP_SHA1 = CScriptOp(0xa7)
OP_SHA256 = CScriptOp(0xa8)
OP_HASH160 = CScriptOp(0xa9)
OP_HASH256 = CScriptOp(0xaa)
OP_CODESEPARATOR = CScriptOp(0xab)
OP_CHECKSIG = CScriptOp(0xac)
OP_CHECKSIGVERIFY = CScriptOp(0xad)
OP_CHECKMULTISIG = CScriptOp(0xae)
OP_CHECKMULTISIGVERIFY = CScriptOp(0xaf)
# expansion
OP_NOP1 = CScriptOp(0xb0)
OP_CHECKLOCKTIMEVERIFY = CScriptOp(0xb1)
OP_CHECKSEQUENCEVERIFY = CScriptOp(0xb2)
OP_NOP4 = CScriptOp(0xb3)
OP_NOP5 = CScriptOp(0xb4)
OP_NOP6 = CScriptOp(0xb5)
OP_NOP7 = CScriptOp(0xb6)
OP_NOP8 = CScriptOp(0xb7)
OP_NOP9 = CScriptOp(0xb8)
OP_NOP10 = CScriptOp(0xb9)
# BIP 342 opcodes (Tapscript)
OP_CHECKSIGADD = CScriptOp(0xba)
OP_INVALIDOPCODE = CScriptOp(0xff)
OPCODE_NAMES.update({
OP_0: 'OP_0',
OP_PUSHDATA1: 'OP_PUSHDATA1',
OP_PUSHDATA2: 'OP_PUSHDATA2',
OP_PUSHDATA4: 'OP_PUSHDATA4',
OP_1NEGATE: 'OP_1NEGATE',
OP_RESERVED: 'OP_RESERVED',
OP_1: 'OP_1',
OP_2: 'OP_2',
OP_3: 'OP_3',
OP_4: 'OP_4',
OP_5: 'OP_5',
OP_6: 'OP_6',
OP_7: 'OP_7',
OP_8: 'OP_8',
OP_9: 'OP_9',
OP_10: 'OP_10',
OP_11: 'OP_11',
OP_12: 'OP_12',
OP_13: 'OP_13',
OP_14: 'OP_14',
OP_15: 'OP_15',
OP_16: 'OP_16',
OP_NOP: 'OP_NOP',
OP_VER: 'OP_VER',
OP_IF: 'OP_IF',
OP_NOTIF: 'OP_NOTIF',
OP_VERIF: 'OP_VERIF',
OP_VERNOTIF: 'OP_VERNOTIF',
OP_ELSE: 'OP_ELSE',
OP_ENDIF: 'OP_ENDIF',
OP_VERIFY: 'OP_VERIFY',
OP_RETURN: 'OP_RETURN',
OP_TOALTSTACK: 'OP_TOALTSTACK',
OP_FROMALTSTACK: 'OP_FROMALTSTACK',
OP_2DROP: 'OP_2DROP',
OP_2DUP: 'OP_2DUP',
OP_3DUP: 'OP_3DUP',
OP_2OVER: 'OP_2OVER',
OP_2ROT: 'OP_2ROT',
OP_2SWAP: 'OP_2SWAP',
OP_IFDUP: 'OP_IFDUP',
OP_DEPTH: 'OP_DEPTH',
OP_DROP: 'OP_DROP',
OP_DUP: 'OP_DUP',
OP_NIP: 'OP_NIP',
OP_OVER: 'OP_OVER',
OP_PICK: 'OP_PICK',
OP_ROLL: 'OP_ROLL',
OP_ROT: 'OP_ROT',
OP_SWAP: 'OP_SWAP',
OP_TUCK: 'OP_TUCK',
OP_CAT: 'OP_CAT',
OP_SUBSTR: 'OP_SUBSTR',
OP_LEFT: 'OP_LEFT',
OP_RIGHT: 'OP_RIGHT',
OP_SIZE: 'OP_SIZE',
OP_INVERT: 'OP_INVERT',
OP_AND: 'OP_AND',
OP_OR: 'OP_OR',
OP_XOR: 'OP_XOR',
OP_EQUAL: 'OP_EQUAL',
OP_EQUALVERIFY: 'OP_EQUALVERIFY',
OP_RESERVED1: 'OP_RESERVED1',
OP_RESERVED2: 'OP_RESERVED2',
OP_1ADD: 'OP_1ADD',
OP_1SUB: 'OP_1SUB',
OP_2MUL: 'OP_2MUL',
OP_2DIV: 'OP_2DIV',
OP_NEGATE: 'OP_NEGATE',
OP_ABS: 'OP_ABS',
OP_NOT: 'OP_NOT',
OP_0NOTEQUAL: 'OP_0NOTEQUAL',
OP_ADD: 'OP_ADD',
OP_SUB: 'OP_SUB',
OP_MUL: 'OP_MUL',
OP_DIV: 'OP_DIV',
OP_MOD: 'OP_MOD',
OP_LSHIFT: 'OP_LSHIFT',
OP_RSHIFT: 'OP_RSHIFT',
OP_BOOLAND: 'OP_BOOLAND',
OP_BOOLOR: 'OP_BOOLOR',
OP_NUMEQUAL: 'OP_NUMEQUAL',
OP_NUMEQUALVERIFY: 'OP_NUMEQUALVERIFY',
OP_NUMNOTEQUAL: 'OP_NUMNOTEQUAL',
OP_LESSTHAN: 'OP_LESSTHAN',
OP_GREATERTHAN: 'OP_GREATERTHAN',
OP_LESSTHANOREQUAL: 'OP_LESSTHANOREQUAL',
OP_GREATERTHANOREQUAL: 'OP_GREATERTHANOREQUAL',
OP_MIN: 'OP_MIN',
OP_MAX: 'OP_MAX',
OP_WITHIN: 'OP_WITHIN',
OP_RIPEMD160: 'OP_RIPEMD160',
OP_SHA1: 'OP_SHA1',
OP_SHA256: 'OP_SHA256',
OP_HASH160: 'OP_HASH160',
OP_HASH256: 'OP_HASH256',
OP_CODESEPARATOR: 'OP_CODESEPARATOR',
OP_CHECKSIG: 'OP_CHECKSIG',
OP_CHECKSIGVERIFY: 'OP_CHECKSIGVERIFY',
OP_CHECKMULTISIG: 'OP_CHECKMULTISIG',
OP_CHECKMULTISIGVERIFY: 'OP_CHECKMULTISIGVERIFY',
OP_NOP1: 'OP_NOP1',
OP_CHECKLOCKTIMEVERIFY: 'OP_CHECKLOCKTIMEVERIFY',
OP_CHECKSEQUENCEVERIFY: 'OP_CHECKSEQUENCEVERIFY',
OP_NOP4: 'OP_NOP4',
OP_NOP5: 'OP_NOP5',
OP_NOP6: 'OP_NOP6',
OP_NOP7: 'OP_NOP7',
OP_NOP8: 'OP_NOP8',
OP_NOP9: 'OP_NOP9',
OP_NOP10: 'OP_NOP10',
OP_CHECKSIGADD: 'OP_CHECKSIGADD',
OP_INVALIDOPCODE: 'OP_INVALIDOPCODE',
})
class CScriptInvalidError(Exception):
"""Base class for CScript exceptions"""
pass
class CScriptTruncatedPushDataError(CScriptInvalidError):
"""Invalid pushdata due to truncation"""
def __init__(self, msg, data):
self.data = data
super().__init__(msg)
# This is used, eg, for blockchain heights in coinbase scripts (bip34)
class CScriptNum:
__slots__ = ("value",)
def __init__(self, d=0):
self.value = d
@staticmethod
def encode(obj):
r = bytearray(0)
if obj.value == 0:
return bytes(r)
neg = obj.value < 0
absvalue = -obj.value if neg else obj.value
while (absvalue):
r.append(absvalue & 0xff)
absvalue >>= 8
if r[-1] & 0x80:
r.append(0x80 if neg else 0)
elif neg:
r[-1] |= 0x80
return bytes([len(r)]) + r
@staticmethod
def decode(vch):
result = 0
# We assume valid push_size and minimal encoding
value = vch[1:]
if len(value) == 0:
return result
for i, byte in enumerate(value):
result |= int(byte) << 8 * i
if value[-1] >= 0x80:
# Mask for all but the highest result bit
num_mask = (2**(len(value) * 8) - 1) >> 1
result &= num_mask
result *= -1
return result
class CScript(bytes):
"""Serialized script
A bytes subclass, so you can use this directly whenever bytes are accepted.
Note that this means that indexing does *not* work - you'll get an index by
byte rather than opcode. This format was chosen for efficiency so that the
general case would not require creating a lot of little CScriptOP objects.
iter(script) however does iterate by opcode.
"""
__slots__ = ()
@classmethod
def __coerce_instance(cls, other):
# Coerce other into bytes
if isinstance(other, CScriptOp):
other = bytes([other])
elif isinstance(other, CScriptNum):
if (other.value == 0):
other = bytes([CScriptOp(OP_0)])
else:
other = CScriptNum.encode(other)
elif isinstance(other, int):
if 0 <= other <= 16:
other = bytes([CScriptOp.encode_op_n(other)])
elif other == -1:
other = bytes([OP_1NEGATE])
else:
other = CScriptOp.encode_op_pushdata(bn2vch(other))
elif isinstance(other, (bytes, bytearray)):
other = CScriptOp.encode_op_pushdata(other)
return other
def __add__(self, other):
# add makes no sense for a CScript()
raise NotImplementedError
def join(self, iterable):
# join makes no sense for a CScript()
raise NotImplementedError
def __new__(cls, value=b''):
if isinstance(value, bytes) or isinstance(value, bytearray):
return super().__new__(cls, value)
else:
def coerce_iterable(iterable):
for instance in iterable:
yield cls.__coerce_instance(instance)
# Annoyingly on both python2 and python3 bytes.join() always
# returns a bytes instance even when subclassed.
return super().__new__(cls, b''.join(coerce_iterable(value)))
def raw_iter(self):
"""Raw iteration
Yields tuples of (opcode, data, sop_idx) so that the different possible
PUSHDATA encodings can be accurately distinguished, as well as
determining the exact opcode byte indexes. (sop_idx)
"""
i = 0
while i < len(self):
sop_idx = i
opcode = CScriptOp(self[i])
i += 1
if opcode > OP_PUSHDATA4:
yield (opcode, None, sop_idx)
else:
datasize = None
pushdata_type = None
if opcode < OP_PUSHDATA1:
pushdata_type = 'PUSHDATA(%d)' % opcode
datasize = opcode
elif opcode == OP_PUSHDATA1:
pushdata_type = 'PUSHDATA1'
if i >= len(self):
raise CScriptInvalidError('PUSHDATA1: missing data length')
datasize = self[i]
i += 1
elif opcode == OP_PUSHDATA2:
pushdata_type = 'PUSHDATA2'
if i + 1 >= len(self):
raise CScriptInvalidError('PUSHDATA2: missing data length')
datasize = self[i] + (self[i + 1] << 8)
i += 2
elif opcode == OP_PUSHDATA4:
pushdata_type = 'PUSHDATA4'
if i + 3 >= len(self):
raise CScriptInvalidError('PUSHDATA4: missing data length')
datasize = self[i] + (self[i + 1] << 8) + (self[i + 2] << 16) + (self[i + 3] << 24)
i += 4
else:
assert False # shouldn't happen
data = bytes(self[i:i + datasize])
# Check for truncation
if len(data) < datasize:
raise CScriptTruncatedPushDataError('%s: truncated data' % pushdata_type, data)
i += datasize
yield (opcode, data, sop_idx)
def __iter__(self):
"""'Cooked' iteration
Returns either a CScriptOP instance, an integer, or bytes, as
appropriate.
See raw_iter() if you need to distinguish the different possible
PUSHDATA encodings.
"""
for (opcode, data, sop_idx) in self.raw_iter():
if data is not None:
yield data
else:
opcode = CScriptOp(opcode)
if opcode.is_small_int():
yield opcode.decode_op_n()
else:
yield CScriptOp(opcode)
def __repr__(self):
def _repr(o):
if isinstance(o, bytes):
return "x('%s')" % o.hex()
else:
return repr(o)
ops = []
i = iter(self)
while True:
op = None
try:
op = _repr(next(i))
except CScriptTruncatedPushDataError as err:
op = '%s...<ERROR: %s>' % (_repr(err.data), err)
break
except CScriptInvalidError as err:
op = '<ERROR: %s>' % err
break
except StopIteration:
break
finally:
if op is not None:
ops.append(op)
return "CScript([%s])" % ', '.join(ops)
def GetSigOpCount(self, fAccurate):
"""Get the SigOp count.
fAccurate - Accurately count CHECKMULTISIG, see BIP16 for details.
Note that this is consensus-critical.
"""
n = 0
lastOpcode = OP_INVALIDOPCODE
for (opcode, data, sop_idx) in self.raw_iter():
if opcode in (OP_CHECKSIG, OP_CHECKSIGVERIFY):
n += 1
elif opcode in (OP_CHECKMULTISIG, OP_CHECKMULTISIGVERIFY):
if fAccurate and (OP_1 <= lastOpcode <= OP_16):
n += lastOpcode.decode_op_n()
else:
n += 20
lastOpcode = opcode
return n
def IsWitnessProgram(self):
"""A witness program is any valid CScript that consists of a 1-byte
push opcode followed by a data push between 2 and 40 bytes."""
return ((4 <= len(self) <= 42) and
(self[0] == OP_0 or (OP_1 <= self[0] <= OP_16)) and
(self[1] + 2 == len(self)))
SIGHASH_DEFAULT = 0 # Taproot-only default, semantics same as SIGHASH_ALL
SIGHASH_ALL = 1
SIGHASH_NONE = 2
SIGHASH_SINGLE = 3
SIGHASH_ANYONECANPAY = 0x80
def FindAndDelete(script, sig):
"""Consensus critical, see FindAndDelete() in Satoshi codebase"""
r = b''
last_sop_idx = sop_idx = 0
skip = True
for (opcode, data, sop_idx) in script.raw_iter():
if not skip:
r += script[last_sop_idx:sop_idx]
last_sop_idx = sop_idx
if script[sop_idx:sop_idx + len(sig)] == sig:
skip = True
else:
skip = False
if not skip:
r += script[last_sop_idx:]
return CScript(r)
def LegacySignatureMsg(script, txTo, inIdx, hashtype):
"""Preimage of the signature hash, if it exists.
Returns either (None, err) to indicate error (which translates to sighash 1),
or (msg, None).
"""
if inIdx >= len(txTo.vin):
return (None, "inIdx %d out of range (%d)" % (inIdx, len(txTo.vin)))
txtmp = CTransaction(txTo)
for txin in txtmp.vin:
txin.scriptSig = b''
txtmp.vin[inIdx].scriptSig = FindAndDelete(script, CScript([OP_CODESEPARATOR]))
if (hashtype & 0x1f) == SIGHASH_NONE:
txtmp.vout = []
for i in range(len(txtmp.vin)):
if i != inIdx:
txtmp.vin[i].nSequence = 0
elif (hashtype & 0x1f) == SIGHASH_SINGLE:
outIdx = inIdx
if outIdx >= len(txtmp.vout):
return (None, "outIdx %d out of range (%d)" % (outIdx, len(txtmp.vout)))
tmp = txtmp.vout[outIdx]
txtmp.vout = []
for _ in range(outIdx):
txtmp.vout.append(CTxOut(-1))
txtmp.vout.append(tmp)
for i in range(len(txtmp.vin)):
if i != inIdx:
txtmp.vin[i].nSequence = 0
if hashtype & SIGHASH_ANYONECANPAY:
tmp = txtmp.vin[inIdx]
txtmp.vin = []
txtmp.vin.append(tmp)
s = txtmp.serialize_without_witness()
s += hashtype.to_bytes(4, "little")
return (s, None)
def LegacySignatureHash(*args, **kwargs):
"""Consensus-correct SignatureHash
Returns (hash, err) to precisely match the consensus-critical behavior of
the SIGHASH_SINGLE bug. (inIdx is *not* checked for validity)
"""
HASH_ONE = b'\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
msg, err = LegacySignatureMsg(*args, **kwargs)
if msg is None:
return (HASH_ONE, err)
else:
return (hash256(msg), err)
def sign_input_legacy(tx, input_index, input_scriptpubkey, privkey, sighash_type=SIGHASH_ALL):
"""Add legacy ECDSA signature for a given transaction input. Note that the signature
is prepended to the scriptSig field, i.e. additional data pushes necessary for more
complex spends than P2PK (e.g. pubkey for P2PKH) can be already set before."""
(sighash, err) = LegacySignatureHash(input_scriptpubkey, tx, input_index, sighash_type)
assert err is None
der_sig = privkey.sign_ecdsa(sighash)
tx.vin[input_index].scriptSig = bytes(CScript([der_sig + bytes([sighash_type])])) + tx.vin[input_index].scriptSig
tx.rehash()
def sign_input_segwitv0(tx, input_index, input_scriptpubkey, input_amount, privkey, sighash_type=SIGHASH_ALL):
"""Add segwitv0 ECDSA signature for a given transaction input. Note that the signature
is inserted at the bottom of the witness stack, i.e. additional witness data
needed (e.g. pubkey for P2WPKH) can already be set before."""
sighash = SegwitV0SignatureHash(input_scriptpubkey, tx, input_index, sighash_type, input_amount)
der_sig = privkey.sign_ecdsa(sighash)
tx.wit.vtxinwit[input_index].scriptWitness.stack.insert(0, der_sig + bytes([sighash_type]))
tx.rehash()
# TODO: Allow cached hashPrevouts/hashSequence/hashOutputs to be provided.
# Performance optimization probably not necessary for python tests, however.
# Note that this corresponds to sigversion == 1 in EvalScript, which is used
# for version 0 witnesses.
def SegwitV0SignatureMsg(script, txTo, inIdx, hashtype, amount):
hashPrevouts = 0
hashSequence = 0
hashOutputs = 0
if not (hashtype & SIGHASH_ANYONECANPAY):
serialize_prevouts = bytes()
for i in txTo.vin:
serialize_prevouts += i.prevout.serialize()
hashPrevouts = uint256_from_str(hash256(serialize_prevouts))
if (not (hashtype & SIGHASH_ANYONECANPAY) and (hashtype & 0x1f) != SIGHASH_SINGLE and (hashtype & 0x1f) != SIGHASH_NONE):
serialize_sequence = bytes()
for i in txTo.vin:
serialize_sequence += i.nSequence.to_bytes(4, "little")
hashSequence = uint256_from_str(hash256(serialize_sequence))
if ((hashtype & 0x1f) != SIGHASH_SINGLE and (hashtype & 0x1f) != SIGHASH_NONE):
serialize_outputs = bytes()
for o in txTo.vout:
serialize_outputs += o.serialize()
hashOutputs = uint256_from_str(hash256(serialize_outputs))
elif ((hashtype & 0x1f) == SIGHASH_SINGLE and inIdx < len(txTo.vout)):
serialize_outputs = txTo.vout[inIdx].serialize()
hashOutputs = uint256_from_str(hash256(serialize_outputs))
ss = bytes()
ss += txTo.version.to_bytes(4, "little")
ss += ser_uint256(hashPrevouts)
ss += ser_uint256(hashSequence)
ss += txTo.vin[inIdx].prevout.serialize()
ss += ser_string(script)
ss += amount.to_bytes(8, "little", signed=True)
ss += txTo.vin[inIdx].nSequence.to_bytes(4, "little")
ss += ser_uint256(hashOutputs)
ss += txTo.nLockTime.to_bytes(4, "little")
ss += hashtype.to_bytes(4, "little")
return ss
def SegwitV0SignatureHash(*args, **kwargs):
return hash256(SegwitV0SignatureMsg(*args, **kwargs))
class TestFrameworkScript(unittest.TestCase):
def test_bn2vch(self):
self.assertEqual(bn2vch(0), bytes([]))
self.assertEqual(bn2vch(1), bytes([0x01]))
self.assertEqual(bn2vch(-1), bytes([0x81]))
self.assertEqual(bn2vch(0x7F), bytes([0x7F]))
self.assertEqual(bn2vch(-0x7F), bytes([0xFF]))
self.assertEqual(bn2vch(0x80), bytes([0x80, 0x00]))
self.assertEqual(bn2vch(-0x80), bytes([0x80, 0x80]))
self.assertEqual(bn2vch(0xFF), bytes([0xFF, 0x00]))
self.assertEqual(bn2vch(-0xFF), bytes([0xFF, 0x80]))
self.assertEqual(bn2vch(0x100), bytes([0x00, 0x01]))
self.assertEqual(bn2vch(-0x100), bytes([0x00, 0x81]))
self.assertEqual(bn2vch(0x7FFF), bytes([0xFF, 0x7F]))
self.assertEqual(bn2vch(-0x8000), bytes([0x00, 0x80, 0x80]))
self.assertEqual(bn2vch(-0x7FFFFF), bytes([0xFF, 0xFF, 0xFF]))
self.assertEqual(bn2vch(0x80000000), bytes([0x00, 0x00, 0x00, 0x80, 0x00]))
self.assertEqual(bn2vch(-0x80000000), bytes([0x00, 0x00, 0x00, 0x80, 0x80]))
self.assertEqual(bn2vch(0xFFFFFFFF), bytes([0xFF, 0xFF, 0xFF, 0xFF, 0x00]))
self.assertEqual(bn2vch(123456789), bytes([0x15, 0xCD, 0x5B, 0x07]))
self.assertEqual(bn2vch(-54321), bytes([0x31, 0xD4, 0x80]))
def test_cscriptnum_encoding(self):
# round-trip negative and multi-byte CScriptNums
values = [0, 1, -1, -2, 127, 128, -255, 256, (1 << 15) - 1, -(1 << 16), (1 << 24) - 1, (1 << 31), 1 - (1 << 32), 1 << 40, 1500, -1500]
for value in values:
self.assertEqual(CScriptNum.decode(CScriptNum.encode(CScriptNum(value))), value)
def test_legacy_sigopcount(self):
# test repeated single sig ops
for n_ops in range(1, 100, 10):
for singlesig_op in (OP_CHECKSIG, OP_CHECKSIGVERIFY):
singlesigs_script = CScript([singlesig_op]*n_ops)
self.assertEqual(singlesigs_script.GetSigOpCount(fAccurate=False), n_ops)
self.assertEqual(singlesigs_script.GetSigOpCount(fAccurate=True), n_ops)
# test multisig op (including accurate counting, i.e. BIP16)
for n in range(1, 16+1):
for multisig_op in (OP_CHECKMULTISIG, OP_CHECKMULTISIGVERIFY):
multisig_script = CScript([CScriptOp.encode_op_n(n), multisig_op])
self.assertEqual(multisig_script.GetSigOpCount(fAccurate=False), 20)
self.assertEqual(multisig_script.GetSigOpCount(fAccurate=True), n)
def BIP341_sha_prevouts(txTo):
return sha256(b"".join(i.prevout.serialize() for i in txTo.vin))
def BIP341_sha_amounts(spent_utxos):
return sha256(b"".join(u.nValue.to_bytes(8, "little", signed=True) for u in spent_utxos))
def BIP341_sha_scriptpubkeys(spent_utxos):
return sha256(b"".join(ser_string(u.scriptPubKey) for u in spent_utxos))
def BIP341_sha_sequences(txTo):
return sha256(b"".join(i.nSequence.to_bytes(4, "little") for i in txTo.vin))
def BIP341_sha_outputs(txTo):
return sha256(b"".join(o.serialize() for o in txTo.vout))
def TaprootSignatureMsg(txTo, spent_utxos, hash_type, input_index=0, *, scriptpath=False, leaf_script=None, codeseparator_pos=-1, annex=None, leaf_ver=LEAF_VERSION_TAPSCRIPT):
assert (len(txTo.vin) == len(spent_utxos))
assert (input_index < len(txTo.vin))
out_type = SIGHASH_ALL if hash_type == 0 else hash_type & 3
in_type = hash_type & SIGHASH_ANYONECANPAY
spk = spent_utxos[input_index].scriptPubKey
ss = bytes([0, hash_type]) # epoch, hash_type
ss += txTo.version.to_bytes(4, "little")
ss += txTo.nLockTime.to_bytes(4, "little")
if in_type != SIGHASH_ANYONECANPAY:
ss += BIP341_sha_prevouts(txTo)
ss += BIP341_sha_amounts(spent_utxos)
ss += BIP341_sha_scriptpubkeys(spent_utxos)
ss += BIP341_sha_sequences(txTo)
if out_type == SIGHASH_ALL:
ss += BIP341_sha_outputs(txTo)
spend_type = 0
if annex is not None:
spend_type |= 1
if scriptpath:
spend_type |= 2
ss += bytes([spend_type])
if in_type == SIGHASH_ANYONECANPAY:
ss += txTo.vin[input_index].prevout.serialize()
ss += spent_utxos[input_index].nValue.to_bytes(8, "little", signed=True)
ss += ser_string(spk)
ss += txTo.vin[input_index].nSequence.to_bytes(4, "little")
else:
ss += input_index.to_bytes(4, "little")
if (spend_type & 1):
ss += sha256(ser_string(annex))
if out_type == SIGHASH_SINGLE:
if input_index < len(txTo.vout):
ss += sha256(txTo.vout[input_index].serialize())
else:
ss += bytes(0 for _ in range(32))
if scriptpath:
ss += TaggedHash("TapLeaf", bytes([leaf_ver]) + ser_string(leaf_script))
ss += bytes([0])
ss += codeseparator_pos.to_bytes(4, "little", signed=True)
assert len(ss) == 175 - (in_type == SIGHASH_ANYONECANPAY) * 49 - (out_type != SIGHASH_ALL and out_type != SIGHASH_SINGLE) * 32 + (annex is not None) * 32 + scriptpath * 37
return ss
def TaprootSignatureHash(*args, **kwargs):
return TaggedHash("TapSighash", TaprootSignatureMsg(*args, **kwargs))
def taproot_tree_helper(scripts):
if len(scripts) == 0:
return ([], bytes())
if len(scripts) == 1:
# One entry: treat as a leaf
script = scripts[0]
assert not callable(script)
if isinstance(script, list):
return taproot_tree_helper(script)
assert isinstance(script, tuple)
version = LEAF_VERSION_TAPSCRIPT
name = script[0]
code = script[1]
if len(script) == 3:
version = script[2]
assert version & 1 == 0
assert isinstance(code, bytes)
h = TaggedHash("TapLeaf", bytes([version]) + ser_string(code))
if name is None:
return ([], h)
return ([(name, version, code, bytes(), h)], h)
elif len(scripts) == 2 and callable(scripts[1]):
# Two entries, and the right one is a function
left, left_h = taproot_tree_helper(scripts[0:1])
right_h = scripts[1](left_h)
left = [(name, version, script, control + right_h, leaf) for name, version, script, control, leaf in left]
right = []
else:
# Two or more entries: descend into each side
split_pos = len(scripts) // 2
left, left_h = taproot_tree_helper(scripts[0:split_pos])
right, right_h = taproot_tree_helper(scripts[split_pos:])
left = [(name, version, script, control + right_h, leaf) for name, version, script, control, leaf in left]
right = [(name, version, script, control + left_h, leaf) for name, version, script, control, leaf in right]
if right_h < left_h:
right_h, left_h = left_h, right_h
h = TaggedHash("TapBranch", left_h + right_h)
return (left + right, h)
# A TaprootInfo object has the following fields:
# - scriptPubKey: the scriptPubKey (witness v1 CScript)
# - internal_pubkey: the internal pubkey (32 bytes)
# - negflag: whether the pubkey in the scriptPubKey was negated from internal_pubkey+tweak*G (bool).
# - tweak: the tweak (32 bytes)
# - leaves: a dict of name -> TaprootLeafInfo objects for all known leaves
# - merkle_root: the script tree's Merkle root, or bytes() if no leaves are present
TaprootInfo = namedtuple("TaprootInfo", "scriptPubKey,internal_pubkey,negflag,tweak,leaves,merkle_root,output_pubkey")
# A TaprootLeafInfo object has the following fields:
# - script: the leaf script (CScript or bytes)
# - version: the leaf version (0xc0 for BIP342 tapscript)
# - merklebranch: the merkle branch to use for this leaf (32*N bytes)
TaprootLeafInfo = namedtuple("TaprootLeafInfo", "script,version,merklebranch,leaf_hash")
def taproot_construct(pubkey, scripts=None, treat_internal_as_infinity=False):
"""Construct a tree of Taproot spending conditions
pubkey: a 32-byte xonly pubkey for the internal pubkey (bytes)
scripts: a list of items; each item is either:
- a (name, CScript or bytes, leaf version) tuple
- a (name, CScript or bytes) tuple (defaulting to leaf version 0xc0)
- another list of items (with the same structure)
- a list of two items; the first of which is an item itself, and the
second is a function. The function takes as input the Merkle root of the
first item, and produces a (fictitious) partner to hash with.
Returns: a TaprootInfo object
"""
if scripts is None:
scripts = []
ret, h = taproot_tree_helper(scripts)
tweak = TaggedHash("TapTweak", pubkey + h)
if treat_internal_as_infinity:
tweaked, negated = compute_xonly_pubkey(tweak)
else:
tweaked, negated = tweak_add_pubkey(pubkey, tweak)
leaves = dict((name, TaprootLeafInfo(script, version, merklebranch, leaf)) for name, version, script, merklebranch, leaf in ret)
return TaprootInfo(CScript([OP_1, tweaked]), pubkey, negated + 0, tweak, leaves, h, tweaked)
def is_op_success(o):
return o == 0x50 or o == 0x62 or o == 0x89 or o == 0x8a or o == 0x8d or o == 0x8e or (o >= 0x7e and o <= 0x81) or (o >= 0x83 and o <= 0x86) or (o >= 0x95 and o <= 0x99) or (o >= 0xbb and o <= 0xfe)
