def __init__(self, height, raw_script, sequence=MAX_INT, block_version=3):
self.height = height
if block_version == 1:
scr = raw_script
else:
scr = Script.build_push_int(self.height) + raw_script
# Coinbase scripts are basically whatever, so we don't
# try to create a script object from them.
super().__init__(self.NULL_OUTPOINT, self.MAX_INT, scr, sequence)
def sign_input(self, input_index, hash_type, private_key, sub_script):
""" Signs an input.
Args:
input_index (int): The index of the input to sign.
hash_type (int): What kind of signature hash to do.
private_key (crypto.PrivateKey): private key with which
to sign the transaction.
sub_script (Script): the scriptPubKey of the corresponding
utxo being spent if the outpoint is P2PKH or the redeem
script if the outpoint is P2SH.
"""
if input_index < 0 or input_index >= len(self.inputs):
raise ValueError("Invalid input index.")
inp = self.inputs[input_index]
multisig = False
if sub_script.is_multisig_redeem():
multisig = True
elif not sub_script.is_p2pkh():
raise TypeError(
"Signing arbitrary redeem scripts is not currently supported.")
tmp_script = sub_script.remove_op("OP_CODESEPARATOR")
# Before signing we should verify that the address in the
# sub_script corresponds to that of the private key
m = self._match_public_key(private_key, tmp_script)
if not m['match']:
if multisig:
msg = "Public key derived from private key does not match any of the public keys in redeem script."
else:
msg = "Address derived from private key does not match sub_script!"
raise ValueError(msg)
sig, signed_message = self.get_signature_for_input(
input_index, hash_type, private_key, sub_script)
if multisig:
# For multisig, we need to determine if there are already
# signatures and if so, where we insert this signature
inp.script = self._do_multisig_script(
[dict(index=m['info']['multisig_key_index'], signature=sig)],
signed_message, inp.script, tmp_script, hash_type)
else:
pub_key_bytes = self._get_public_key_bytes(private_key,
m['info']['compressed'])
inp.script = Script(
[sig.to_der() + pack_compact_int(hash_type), pub_key_bytes])
return True
def _copy_for_sig(self, input_index, hash_type, sub_script):
""" Returns a copy of this txn appropriate for signing, based
on hash_type.
"""
new_txn = copy.deepcopy(self)
# First deal w/the inputs
# For the SIG_HASH_ANY case, we only care about
# self.inputs[input_index]
if hash_type == self.SIG_HASH_ANY:
ti = new_txn.inputs[input_index]
new_txn.inputs = [ti]
else:
for i, inp in enumerate(new_txn.inputs):
inp.script = sub_script if i == input_index else Script("")
if hash_type & 0x1f in [
self.SIG_HASH_NONE, self.SIG_HASH_SINGLE
] and input_index != i:
# Sequence numbers (nSequence) must be set to 0 for all but
# the input we care about.
inp.sequence_num = 0
# Now deal with outputs
if hash_type & 0x1f == self.SIG_HASH_NONE:
new_txn.outputs = []
elif hash_type & 0x1f == self.SIG_HASH_SINGLE:
# Resize output vector to input_index + 1
new_txn.outputs = new_txn.outputs[:input_index + 1]
# All outputs except outputs[i] have a value of -1 (0xffffffff)
# and a blank script
for i, out in enumerate(new_txn.outputs):
if i != input_index:
out.script = Script("")
out.value = 0xffffffff
return new_txn
def from_bytes(b):
""" Deserializes a byte stream into a TransactionOutput object.
Args:
b (bytes): byte-stream beginning with the value.
Returns:
tuple:
First element of the tuple is a TransactionOutput,
the second is the remainder of the byte stream.
"""
value, b0 = unpack_u64(b)
script_len, b0 = unpack_compact_int(b0)
return (TransactionOutput(value,
Script(b0[:script_len])), b0[script_len:])
def _verify_input(self, input_index, sub_script, partial_multisig=False):
p2sh = sub_script.is_p2sh()
sig_script = self.inputs[input_index].script
si = ScriptInterpreter(txn=self,
input_index=input_index,
sub_script=sub_script)
try:
si.run_script(sig_script)
except ScriptInterpreterError:
return False
# This copy_stack and the restore_stack emulate the behavior
# found in bitcoin core for evaluating P2SH scripts. See:
# https://github.com/bitcoin/bitcoin/blob/master/src/script/interpreter.cpp#L1170
if p2sh:
si.copy_stack()
try:
si.run_script(sub_script)
except ScriptInterpreterError:
return False
rv = si.valid
if p2sh:
si.restore_stack()
redeem_script = Script(si.stack.pop())
si._sub_script = redeem_script
try:
if sig_script.is_multisig_sig() and partial_multisig:
# This is a hack for partial verification
partial_script = copy.deepcopy(redeem_script)
partial_script.ast[-1] = 'OP_CHECKPARTIALMULTISIG'
sig_info = sig_script.extract_multisig_sig_info()
si.run_script(partial_script)
rv &= si.match_count > 0 and si.match_count <= len(
sig_info['signatures'])
else:
si.run_script(redeem_script)
rv &= si.valid
except:
rv = False
return rv
def from_bytes(b):
""" Deserializes a byte stream into a TransactionInput.
Args:
b (bytes): byte stream starting with the outpoint.
Returns:
tuple:
First element of the tuple is the TransactionInput
object and the second is the remaining byte stream.
"""
outpoint = b[0:32]
outpoint_index, b1 = unpack_u32(b[32:])
script, b1 = Script.from_bytes(b1)
sequence_num, b1 = unpack_u32(b1)
return (TransactionInput(Hash(outpoint), outpoint_index, script,
sequence_num), b1)
def _do_multisig_script(self, sigs, message, current_script_sig,
redeem_script, hash_type):
# If the current script is empty or None, create it
sig_script = None
if current_script_sig is None or not str(current_script_sig):
sig_bytes = [
s['signature'].to_der() + pack_compact_int(hash_type)
for s in sigs
]
sig_script = Script.build_multisig_sig(sigs=sig_bytes,
redeem_script=redeem_script)
else:
# Need to extract all the sigs already present
multisig_params = redeem_script.extract_multisig_redeem_info()
sig_info = current_script_sig.extract_multisig_sig_info()
# Do a few quick sanity checks
if str(sig_info['redeem_script']) != str(redeem_script):
raise ValueError(
"Redeem script in signature script does not match redeem_script!"
)
if len(sig_info['signatures']) == multisig_params['n']:
# Already max number of signatures
return current_script_sig
# Go through the signatures and match them up to the public keys
# in the redeem script
pub_keys = []
for pk in multisig_params['public_keys']:
pub_keys.append(crypto.PublicKey.from_bytes(pk))
existing_sigs = []
for s in sig_info['signatures']:
s1, h = s[:-1], s[-1] # Last byte is hash_type
existing_sigs.append(crypto.Signature.from_der(s1))
if h != hash_type:
raise ValueError(
"hash_type does not match that of the existing signatures."
)
# Match them up
existing_sig_indices = self._match_sigs_to_pub_keys(
existing_sigs, pub_keys, message)
sig_indices = {s['index']: s['signature'] for s in sigs}
# Make sure there are no dups
all_indices = set(
list(existing_sig_indices.keys()) + list(sig_indices.keys()))
if len(all_indices) < len(existing_sig_indices) + len(sig_indices):
raise ValueError(
"At least one signature matches an existing signature.")
if len(all_indices) > multisig_params['n']:
raise ValueError("There are too many signatures.")
all_sigs = []
for i in sorted(all_indices):
if i in existing_sig_indices:
all_sigs.append(existing_sig_indices[i])
elif i in sig_indices:
all_sigs.append(sig_indices[i])
all_sigs_bytes = [
s.to_der() + pack_compact_int(hash_type) for s in all_sigs
]
sig_script = Script.build_multisig_sig(all_sigs_bytes,
redeem_script)
return sig_script