# Copyright (C) 2012-2015 The python-bitcoinlib developers
#
# This file is part of python-bitcoinlib.
#
# It is subject to the license terms in the LICENSE file found in the top-level
# directory of this distribution.
#
# No part of python-bitcoinlib, including this file, may be copied, modified,
# propagated, or distributed except according to the terms contained in the
# LICENSE file.
"""Scripts
Functionality to build scripts, as well as SignatureHash(). Script evaluation
is in bitcoincash.core.scripteval
"""
from __future__ import absolute_import, division, print_function
import sys
_bchr = chr
_bord = ord
if sys.version > '3':
long = int
_bchr = lambda x: bytes([x])
_bord = lambda x: x
import struct
import bitcoincash.core
import bitcoincash.core._bignum
from bitcoincash.core.serialize import uint256_from_str, uint256_to_str, ser_string
MAX_SCRIPT_SIZE = 10000
MAX_SCRIPT_ELEMENT_SIZE = 520
MAX_SCRIPT_OPCODES = 201
OPCODE_NAMES = {}
_opcode_instances = []
[docs]class CScriptOp(int):
"""A single script opcode"""
__slots__ = []
[docs] @staticmethod
def encode_op_pushdata(d):
"""Encode a PUSHDATA op, returning bytes"""
if len(d) < 0x4c:
return b'' + _bchr(len(d)) + d # OP_PUSHDATA
elif len(d) <= 0xff:
return b'\x4c' + _bchr(len(d)) + d # OP_PUSHDATA1
elif len(d) <= 0xffff:
return b'\x4d' + struct.pack(b'<H', len(d)) + d # OP_PUSHDATA2
elif len(d) <= 0xffffffff:
return b'\x4e' + struct.pack(b'<I', len(d)) + d # OP_PUSHDATA4
else:
raise ValueError("Data too long to encode in a PUSHDATA op")
[docs] @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)
[docs] 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)
[docs] 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(CScriptOp, cls).__new__(cls, n))
return _opcode_instances[n]
# 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_NOP2 = CScriptOp(0xb1)
OP_CHECKLOCKTIMEVERIFY = OP_NOP2
OP_NOP3 = 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)
# template matching params
OP_SMALLINTEGER = CScriptOp(0xfa)
OP_PUBKEYS = CScriptOp(0xfb)
OP_PUBKEYHASH = CScriptOp(0xfd)
OP_PUBKEY = CScriptOp(0xfe)
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_NOP2: 'OP_NOP2',
OP_CHECKLOCKTIMEVERIFY: 'OP_CHECKLOCKTIMEVERIFY',
OP_NOP3: 'OP_NOP3',
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_SMALLINTEGER: 'OP_SMALLINTEGER',
OP_PUBKEYS: 'OP_PUBKEYS',
OP_PUBKEYHASH: 'OP_PUBKEYHASH',
OP_PUBKEY: 'OP_PUBKEY',
OP_INVALIDOPCODE: 'OP_INVALIDOPCODE',
})
OPCODES_BY_NAME = {
'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_NOP2': OP_NOP2,
'OP_CHECKLOCKTIMEVERIFY': OP_CHECKLOCKTIMEVERIFY,
'OP_NOP3': OP_NOP3,
'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_SMALLINTEGER': OP_SMALLINTEGER,
'OP_PUBKEYS': OP_PUBKEYS,
'OP_PUBKEYHASH': OP_PUBKEYHASH,
'OP_PUBKEY': OP_PUBKEY,
}
# Invalid even when occuring in an unexecuted OP_IF branch due to either being
# disabled, or never having been implemented.
DISABLED_OPCODES = frozenset((OP_VERIF, OP_VERNOTIF,
OP_CAT, OP_SUBSTR, OP_LEFT, OP_RIGHT, OP_INVERT, OP_AND,
OP_OR, OP_XOR, OP_2MUL, OP_2DIV, OP_MUL, OP_DIV, OP_MOD,
OP_LSHIFT, OP_RSHIFT))
[docs]class CScriptInvalidError(Exception):
"""Base class for CScript exceptions"""
pass
[docs]class CScriptTruncatedPushDataError(CScriptInvalidError):
"""Invalid pushdata due to truncation"""
def __init__(self, msg, data):
self.data = data
super(CScriptTruncatedPushDataError, self).__init__(msg)
[docs]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.
"""
@classmethod
def __coerce_instance(cls, other):
# Coerce other into bytes
if isinstance(other, CScriptOp):
other = _bchr(other)
elif isinstance(other, (int, long)):
if 0 <= other <= 16:
other = bytes(_bchr(CScriptOp.encode_op_n(other)))
elif other == -1:
other = bytes(_bchr(OP_1NEGATE))
else:
other = CScriptOp.encode_op_pushdata(bitcoincash.core._bignum.bn2vch(other))
elif isinstance(other, (bytes, bytearray)):
other = CScriptOp.encode_op_pushdata(other)
return other
def __add__(self, other):
# Do the coercion outside of the try block so that errors in it are
# noticed.
other = self.__coerce_instance(other)
try:
# bytes.__add__ always returns bytes instances unfortunately
return CScript(super(CScript, self).__add__(other))
except TypeError:
raise TypeError('Can not add a %r instance to a CScript' % other.__class__)
[docs] 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(CScript, cls).__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(CScript, cls).__new__(cls, b''.join(coerce_iterable(value)))
[docs] 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 = _bord(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 = _bord(self[i])
i += 1
elif opcode == OP_PUSHDATA2:
pushdata_type = 'PUSHDATA2'
if i + 1 >= len(self):
raise CScriptInvalidError('PUSHDATA2: missing data length')
datasize = _bord(self[i]) + (_bord(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 = _bord(self[i]) + (_bord(self[i+1]) << 8) + (_bord(self[i+2]) << 16) + (_bord(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 opcode == 0:
yield 0
elif 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):
# For Python3 compatibility add b before strings so testcases don't
# need to change
def _repr(o):
if isinstance(o, bytes):
return "x('%s')" % bitcoincash.core.b2x(o)
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)
[docs] def is_p2sh(self):
"""Test if the script is a p2sh scriptPubKey
Note that this test is consensus-critical.
"""
return (len(self) == 23 and
_bord(self[0]) == OP_HASH160 and
_bord(self[1]) == 0x14 and
_bord(self[22]) == OP_EQUAL)
[docs] def is_push_only(self):
"""Test if the script only contains pushdata ops
Note that this test is consensus-critical.
Scripts that contain invalid pushdata ops return False, matching the
behavior in Bitcoin Core.
"""
try:
for (op, op_data, idx) in self.raw_iter():
# Note how OP_RESERVED is considered a pushdata op.
if op > OP_16:
return False
except CScriptInvalidError:
return False
return True
[docs] def has_canonical_pushes(self):
"""Test if script only uses canonical pushes
Not yet consensus critical; may be in the future.
"""
try:
for (op, data, idx) in self.raw_iter():
if op > OP_16:
continue
elif op < OP_PUSHDATA1 and op > OP_0 and len(data) == 1 and _bord(data[0]) <= 16:
# Could have used an OP_n code, rather than a 1-byte push.
return False
elif op == OP_PUSHDATA1 and len(data) < OP_PUSHDATA1:
# Could have used a normal n-byte push, rather than OP_PUSHDATA1.
return False
elif op == OP_PUSHDATA2 and len(data) <= 0xFF:
# Could have used a OP_PUSHDATA1.
return False
elif op == OP_PUSHDATA4 and len(data) <= 0xFFFF:
# Could have used a OP_PUSHDATA2.
return False
except CScriptInvalidError: # Invalid pushdata
return False
return True
[docs] def is_unspendable(self):
"""Test if the script is provably unspendable"""
return (len(self) > 0 and
_bord(self[0]) == OP_RETURN)
[docs] def is_valid(self):
"""Return True if the script is valid, False otherwise
The script is valid if all PUSHDATA's are valid; invalid opcodes do not
make is_valid() return False.
"""
try:
list(self)
except CScriptInvalidError:
return False
return True
[docs] def to_p2sh_scriptPubKey(self, checksize=True):
"""Create P2SH scriptPubKey from this redeemScript
That is, create the P2SH scriptPubKey that requires this script as a
redeemScript to spend.
checksize - Check if the redeemScript is larger than the 520-byte max
pushdata limit; raise ValueError if limit exceeded.
Since a >520-byte PUSHDATA makes EvalScript() fail, it's not actually
possible to redeem P2SH outputs with redeem scripts >520 bytes.
"""
if checksize and len(self) > MAX_SCRIPT_ELEMENT_SIZE:
raise ValueError("redeemScript exceeds max allowed size; P2SH output would be unspendable")
return CScript([OP_HASH160, bitcoincash.core.Hash160(self), OP_EQUAL])
[docs] 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 += opcode.decode_op_n()
else:
n += 20
lastOpcode = opcode
return n
SIGHASH_ALL = 1
SIGHASH_NONE = 2
SIGHASH_SINGLE = 3
SIGHASH_FORKID = 0x40
SIGHASH_ANYONECANPAY = 0x80
[docs]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)
[docs]def IsLowDERSignature(sig):
"""
Loosely correlates with IsLowDERSignature() from script/interpreter.cpp
Verifies that the S value in a DER signature is the lowest possible value.
Used by BIP62 malleability fixes.
"""
length_r = sig[3]
if isinstance(length_r, str):
length_r = int(struct.unpack('B', length_r)[0])
length_s = sig[5 + length_r]
if isinstance(length_s, str):
length_s = int(struct.unpack('B', length_s)[0])
s_val = list(struct.unpack(str(length_s) + 'B', sig[6 + length_r:6 + length_r + length_s]))
# If the S value is above the order of the curve divided by two, its
# complement modulo the order could have been used instead, which is
# one byte shorter when encoded correctly.
max_mod_half_order = [
0x7f,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
0x5d,0x57,0x6e,0x73,0x57,0xa4,0x50,0x1d,
0xdf,0xe9,0x2f,0x46,0x68,0x1b,0x20,0xa0]
return CompareBigEndian(s_val, [0]) > 0 and \
CompareBigEndian(s_val, max_mod_half_order) <= 0
def CompareBigEndian(c1, c2):
"""
Loosely matches CompareBigEndian() from eccryptoverify.cpp
Compares two arrays of bytes, and returns a negative value if the first is
less than the second, 0 if they're equal, and a positive value if the
first is greater than the second.
"""
c1 = list(c1)
c2 = list(c2)
# Adjust starting positions until remaining lengths of the two arrays match
while len(c1) > len(c2):
if c1.pop(0) > 0:
return 1
while len(c2) > len(c1):
if c2.pop(0) > 0:
return -1
while len(c1) > 0:
diff = c1.pop(0) - c2.pop(0)
if diff != 0:
return diff
return 0
[docs]def RawSignatureHashLegacy(script, txTo, inIdx, hashtype):
"""Consensus-correct SignatureHash
This is the old signature hash algorithm, before the Bitcoin Cash split
in 2017.
Returns (hash, err) to precisely match the consensus-critical behavior of
the SIGHASH_SINGLE bug. (inIdx is *not* checked for validity)
If you're just writing wallet software you probably want SignatureHash()
instead.
"""
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'
if inIdx >= len(txTo.vin):
return (HASH_ONE, "inIdx %d out of range (%d)" % (inIdx, len(txTo.vin)))
txtmp = bitcoincash.core.CMutableTransaction.from_tx(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 (HASH_ONE, "outIdx %d out of range (%d)" % (outIdx, len(txtmp.vout)))
tmp = txtmp.vout[outIdx]
txtmp.vout = []
for i in range(outIdx):
txtmp.vout.append(bitcoincash.core.CTxOut())
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()
s += struct.pack(b"<i", hashtype)
hash = bitcoincash.core.Hash(s)
return (hash, None)
[docs]def SignatureHashLegacy(script, txTo, inIdx, hashtype):
"""Calculate a signature hash
This is the old signature hash algorithm, before the Bitcoin Cash split
in 2017.
'Cooked' version that checks if inIdx is out of bounds - this is *not*
consensus-correct behavior, but is what you probably want for general
wallet use.
"""
(h, err) = RawSignatureHashLegacy(script, txTo, inIdx, hashtype)
if err is not None:
raise ValueError(err)
return h
[docs]def SignatureHash(script, txTo, inIdx, hashtype, amount, *,
legacy_allow = False, legacy_raw = False):
"""Calculate a signature hash
legacy_allow - Allow hashing using the pre-fork signature hash algorithm
legacy_raw - Don't use the 'Cooked' version that checks if inIdx is out
of bounds.
"""
if not SIGHASH_FORKID & hashtype:
if not legacy_allow:
raise ValueError(
"SignatureHash expects SIGHASH_FORKID flag. "
"If you really want to hash with the old signature hash "
"algoritm, set legacy_allow=True")
elif legacy_raw:
(h, _) = RawSignatureHashLegacy(script, txTo, inIdx, hashtype)
return h
else:
return SignatureHashLegacy(script, txTo, inIdx, hashtype)
if amount is None:
raise ValueError("Cannot hash with new signature hash algorithm when "
"amount is None")
hashPrevouts = 0
hashSequence = 0
hashOutputs = 0
def hash256(x):
import hashlib
sha256 = lambda s: hashlib.new('sha256', s).digest()
return sha256(sha256(x))
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 += struct.pack("<I", i.nSequence)
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 += struct.pack("<i", txTo.nVersion)
ss += uint256_to_str(hashPrevouts)
ss += uint256_to_str(hashSequence)
ss += txTo.vin[inIdx].prevout.serialize()
ss += ser_string(script)
ss += struct.pack("<q", amount)
ss += struct.pack("<I", txTo.vin[inIdx].nSequence)
ss += uint256_to_str(hashOutputs)
ss += struct.pack("<I", txTo.nLockTime)
ss += struct.pack("<i", hashtype)
return hash256(ss)
__all__ = (
'MAX_SCRIPT_SIZE',
'MAX_SCRIPT_ELEMENT_SIZE',
'MAX_SCRIPT_OPCODES',
'OPCODE_NAMES',
'CScriptOp',
# every opcode
'OP_0',
'OP_FALSE',
'OP_PUSHDATA1',
'OP_PUSHDATA2',
'OP_PUSHDATA4',
'OP_1NEGATE',
'OP_RESERVED',
'OP_1',
'OP_TRUE',
'OP_2',
'OP_3',
'OP_4',
'OP_5',
'OP_6',
'OP_7',
'OP_8',
'OP_9',
'OP_10',
'OP_11',
'OP_12',
'OP_13',
'OP_14',
'OP_15',
'OP_16',
'OP_NOP',
'OP_VER',
'OP_IF',
'OP_NOTIF',
'OP_VERIF',
'OP_VERNOTIF',
'OP_ELSE',
'OP_ENDIF',
'OP_VERIFY',
'OP_RETURN',
'OP_TOALTSTACK',
'OP_FROMALTSTACK',
'OP_2DROP',
'OP_2DUP',
'OP_3DUP',
'OP_2OVER',
'OP_2ROT',
'OP_2SWAP',
'OP_IFDUP',
'OP_DEPTH',
'OP_DROP',
'OP_DUP',
'OP_NIP',
'OP_OVER',
'OP_PICK',
'OP_ROLL',
'OP_ROT',
'OP_SWAP',
'OP_TUCK',
'OP_CAT',
'OP_SUBSTR',
'OP_LEFT',
'OP_RIGHT',
'OP_SIZE',
'OP_INVERT',
'OP_AND',
'OP_OR',
'OP_XOR',
'OP_EQUAL',
'OP_EQUALVERIFY',
'OP_RESERVED1',
'OP_RESERVED2',
'OP_1ADD',
'OP_1SUB',
'OP_2MUL',
'OP_2DIV',
'OP_NEGATE',
'OP_ABS',
'OP_NOT',
'OP_0NOTEQUAL',
'OP_ADD',
'OP_SUB',
'OP_MUL',
'OP_DIV',
'OP_MOD',
'OP_LSHIFT',
'OP_RSHIFT',
'OP_BOOLAND',
'OP_BOOLOR',
'OP_NUMEQUAL',
'OP_NUMEQUALVERIFY',
'OP_NUMNOTEQUAL',
'OP_LESSTHAN',
'OP_GREATERTHAN',
'OP_LESSTHANOREQUAL',
'OP_GREATERTHANOREQUAL',
'OP_MIN',
'OP_MAX',
'OP_WITHIN',
'OP_RIPEMD160',
'OP_SHA1',
'OP_SHA256',
'OP_HASH160',
'OP_HASH256',
'OP_CODESEPARATOR',
'OP_CHECKSIG',
'OP_CHECKSIGVERIFY',
'OP_CHECKMULTISIG',
'OP_CHECKMULTISIGVERIFY',
'OP_NOP1',
'OP_NOP2',
'OP_CHECKLOCKTIMEVERIFY',
'OP_NOP3',
'OP_NOP4',
'OP_NOP5',
'OP_NOP6',
'OP_NOP7',
'OP_NOP8',
'OP_NOP9',
'OP_NOP10',
'OP_SMALLINTEGER',
'OP_PUBKEYS',
'OP_PUBKEYHASH',
'OP_PUBKEY',
'OP_INVALIDOPCODE',
'OPCODES_BY_NAME',
'DISABLED_OPCODES',
'CScriptInvalidError',
'CScriptTruncatedPushDataError',
'CScript',
'SIGHASH_ALL',
'SIGHASH_NONE',
'SIGHASH_SINGLE',
'SIGHASH_FORKID',
'SIGHASH_ANYONECANPAY',
'FindAndDelete',
'RawSignatureHashLegacy',
'SignatureHashLegacy',
'SignatureHash',
'IsLowDERSignature',
)