# See the file "LICENSE" for information about the copyright
# and warranty status of this software.
from binascii import hexlify
import struct
from lib.enum import Enumeration
from lib.hash import hash160
from lib.util import cachedproperty
class ScriptError(Exception):
pass
OpCodes = Enumeration("Opcodes", [
("OP_0", 0), ("OP_PUSHDATA1", 76),
"OP_PUSHDATA2", "OP_PUSHDATA4", "OP_1NEGATE",
"OP_RESERVED",
"OP_1", "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_CHECKLOCKTIMEVERIFY", "OP_CHECKSEQUENCEVERIFY"
])
# Paranoia to make it hard to create bad scripts
assert OpCodes.OP_DUP == 0x76
assert OpCodes.OP_HASH160 == 0xa9
assert OpCodes.OP_EQUAL == 0x87
assert OpCodes.OP_EQUALVERIFY == 0x88
assert OpCodes.OP_CHECKSIG == 0xac
assert OpCodes.OP_CHECKMULTISIG == 0xae
class ScriptSig(object):
'''A script from a tx input, typically provides one or more signatures.'''
SIG_ADDRESS, SIG_MULTI, SIG_PUBKEY, SIG_UNKNOWN = range(4)
def __init__(self, script, coin, kind, sigs, pubkeys):
self.script = script
self.coin = coin
self.kind = kind
self.sigs = sigs
self.pubkeys = pubkeys
@cachedproperty
def address(self):
if self.kind == SIG_ADDRESS:
return self.coin.address_from_pubkey(self.pubkeys[0])
if self.kind == SIG_MULTI:
return self.coin.multsig_address(self.pubkeys)
return 'Unknown'
@classmethod
def from_script(cls, script, coin):
'''Returns an instance of this class. Uncrecognised scripts return
an object of kind SIG_UNKNOWN.'''
try:
return cls.parse_script(script, coin)
except ScriptError:
return cls(script, coin, SIG_UNKNOWN, [], [])
@classmethod
def parse_script(cls, script, coin):
'''Returns an instance of this class. Raises on unrecognised
scripts.'''
ops, datas = Script.get_ops(script)
# Address, PubKey and P2SH redeems only push data
if not ops or not Script.match_ops(ops, [-1] * len(ops)):
raise ScriptError('unknown scriptsig pattern')
# Assume double data pushes are address redeems, single data
# pushes are pubkey redeems
if len(ops) == 2: # Signature, pubkey
return cls(script, coin, SIG_ADDRESS, [datas[0]], [datas[1]])
if len(ops) == 1: # Pubkey
return cls(script, coin, SIG_PUBKEY, [datas[0]], [])
# Presumably it is P2SH (though conceivably the above could be
# too; cannot be sure without the send-to script). We only
# handle CHECKMULTISIG P2SH, which because of a bitcoin core
# bug always start with an unused OP_0.
if ops[0] != OpCodes.OP_0:
raise ScriptError('unknown scriptsig pattern; expected OP_0')
# OP_0, Sig1, ..., SigM, pk_script
m = len(ops) - 2
pk_script = datas[-1]
pk_ops, pk_datas = Script.get_ops(script)
# OP_2 pubkey1 pubkey2 pubkey3 OP_3 OP_CHECKMULTISIG
n = len(pk_ops) - 3
pattern = ([OpCodes.OP_1 + m - 1] + [-1] * n
+ [OpCodes.OP_1 + n - 1, OpCodes.OP_CHECKMULTISIG])
if m <= n and Script.match_ops(pk_ops, pattern):
return cls(script, coin, SIG_MULTI, datas[1:-1], pk_datas[1:-2])
raise ScriptError('unknown multisig P2SH pattern')
class ScriptPubKey(object):
'''A script from a tx output that gives conditions necessary for
spending.'''
TO_ADDRESS, TO_P2SH, TO_PUBKEY, TO_UNKNOWN = range(4)
TO_ADDRESS_OPS = [OpCodes.OP_DUP, OpCodes.OP_HASH160, -1,
OpCodes.OP_EQUALVERIFY, OpCodes.OP_CHECKSIG]
TO_P2SH_OPS = [OpCodes.OP_HASH160, -1, OpCodes.OP_EQUAL]
TO_PUBKEY_OPS = [-1, OpCodes.OP_CHECKSIG]
def __init__(self, script, coin, kind, hash168, pubkey=None):
self.script = script
self.coin = coin
self.kind = kind
self.hash168 = hash168
if pubkey:
self.pubkey = pubkey
@cachedproperty
def address(self):
if self.kind == ScriptPubKey.TO_P2SH:
return self.coin.P2SH_address_from_hash160(self.hash168[1:])
if self.hash160:
return self.coin.P2PKH_address_from_hash160(self.hash168[1:])
return ''
@classmethod
def from_script(cls, script, coin):
'''Returns an instance of this class. Uncrecognised scripts return
an object of kind TO_UNKNOWN.'''
try:
return cls.parse_script(script, coin)
except ScriptError:
return cls(script, coin, cls.TO_UNKNOWN, None)
@classmethod
def parse_script(cls, script, coin):
'''Returns an instance of this class. Raises on unrecognised
scripts.'''
ops, datas = Script.get_ops(script)
if Script.match_ops(ops, cls.TO_ADDRESS_OPS):
return cls(script, coin, cls.TO_ADDRESS,
bytes([coin.P2PKH_VERBYTE]) + datas[2])
if Script.match_ops(ops, cls.TO_P2SH_OPS):
return cls(script, coin, cls.TO_P2SH,
bytes([coin.P2SH_VERBYTE]) + datas[1])
if Script.match_ops(ops, cls.TO_PUBKEY_OPS):
pubkey = datas[0]
return cls(script, coin, cls.TO_PUBKEY,
bytes([coin.P2PKH_VERBYTE]) + hash160(pubkey), pubkey)
raise ScriptError('unknown script pubkey pattern')
@classmethod
def P2SH_script(cls, hash160):
return (bytes([OpCodes.OP_HASH160])
+ Script.push_data(hash160)
+ bytes([OpCodes.OP_EQUAL]))
@classmethod
def P2PKH_script(cls, hash160):
return (bytes([OpCodes.OP_DUP, OpCodes.OP_HASH160])
+ Script.push_data(hash160)
+ bytes([OpCodes.OP_EQUALVERIFY, OpCodes.OP_CHECKSIG]))
@classmethod
def validate_pubkey(cls, pubkey, req_compressed=False):
if isinstance(pubkey, (bytes, bytearray)):
if len(pubkey) == 33 and pubkey[0] in (2, 3):
return # Compressed
if len(pubkey) == 65 and pubkey[0] == 4:
if not req_compressed:
return
raise PubKeyError('uncompressed pubkeys are invalid')
raise PubKeyError('invalid pubkey {}'.format(pubkey))
@classmethod
def pubkey_script(cls, pubkey):
cls.validate_pubkey(pubkey)
return Script.push_data(pubkey) + bytes([OpCodes.OP_CHECKSIG])
@classmethod
def multisig_script(cls, m, pubkeys):
'''Returns the script for a pay-to-multisig transaction.'''
n = len(pubkeys)
if not 1 <= m <= n <= 15:
raise ScriptError('{:d} of {:d} multisig script not possible'
.format(m, n))
for pubkey in pubkeys:
cls.validate_pubkey(pubkey, req_compressed=True)
# See https://bitcoin.org/en/developer-guide
# 2 of 3 is: OP_2 pubkey1 pubkey2 pubkey3 OP_3 OP_CHECKMULTISIG
return (bytes([OP_1 + m - 1])
+ b''.join(cls.push_data(pubkey) for pubkey in pubkeys)
+ bytes([OP_1 + n - 1, OP_CHECK_MULTISIG]))
class Script(object):
@classmethod
def get_ops(cls, script):
opcodes, datas = [], []
# The unpacks or script[n] below throw on truncated scripts
try:
n = 0
while n < len(script):
opcode, data = script[n], None
n += 1
if opcode <= OpCodes.OP_PUSHDATA4:
# Raw bytes follow
if opcode < OpCodes.OP_PUSHDATA1:
dlen = opcode
elif opcode == OpCodes.OP_PUSHDATA1:
dlen = script[n]
n += 1
elif opcode == OpCodes.OP_PUSHDATA2:
(dlen,) = struct.unpack('<H', script[n: n + 2])
n += 2
else:
(dlen,) = struct.unpack('<I', script[n: n + 4])
n += 4
data = script[n:n + dlen]
if len(data) != dlen:
raise ScriptError('truncated script')
n += dlen
opcodes.append(opcode)
datas.append(data)
except:
# Truncated script; e.g. tx_hash
# ebc9fa1196a59e192352d76c0f6e73167046b9d37b8302b6bb6968dfd279b767
raise ScriptError('truncated script')
return opcodes, datas
@classmethod
def match_ops(cls, ops, pattern):
if len(ops) != len(pattern):
return False
for op, pop in zip(ops, pattern):
if pop != op:
# -1 Indicates data push expected
if pop == -1 and OpCodes.OP_0 <= op <= OpCodes.OP_PUSHDATA4:
continue
return False
return True
@classmethod
def push_data(cls, data):
'''Returns the opcodes to push the data on the stack.'''
assert isinstance(data, (bytes, bytearray))
n = len(data)
if n < OpCodes.OP_PUSHDATA1:
return bytes([n]) + data
if n < 256:
return bytes([OpCodes.OP_PUSHDATA1, n]) + data
if n < 65536:
return bytes([OpCodes.OP_PUSHDATA2]) + struct.pack('<H', n) + data
return bytes([OpCodes.OP_PUSHDATA4]) + struct.pack('<I', n) + data
@classmethod
def opcode_name(cls, opcode):
if OpCodes.OP_0 < opcode < OpCodes.OP_PUSHDATA1:
return 'OP_{:d}'.format(opcode)
try:
return OpCodes.whatis(opcode)
except KeyError:
return 'OP_UNKNOWN:{:d}'.format(opcode)
@classmethod
def dump(cls, script):
opcodes, datas = cls.get_ops(script)
for opcode, data in zip(opcodes, datas):
name = cls.opcode_name(opcode)
if data is None:
print(name)
else:
print('{} {} ({:d} bytes)'
.format(name, hexlify(data).decode('ascii'), len(data)))