firmware/shared/psbt.py

3653 lines
145 KiB
Python

# (c) Copyright 2018 by Coinkite Inc. This file is covered by license found in COPYING-CC.
#
# psbt.py - understand PSBT file format: verify and generate them
#
import stash, gc, history, sys, ngu, ckcc, chains
from ucollections import OrderedDict
from ustruct import unpack_from, unpack, pack
from ubinascii import hexlify as b2a_hex
from utils import xfp2str, B2A, keypath_to_str, validate_derivation_path_length, problem_file_line, node_from_privkey
from utils import seconds2human_readable, datetime_from_timestamp, datetime_to_str, swab32
from uhashlib import sha256
from uio import BytesIO
from sffile import SizerFile
from chains import taptweak, tapleaf_hash, NLOCK_IS_TIME, AF_TO_STR_AF
from wallet import MiniScriptWallet, TRUST_PSBT, TRUST_VERIFY
from exceptions import FatalPSBTIssue, FraudulentChangeOutput
from serializations import ser_compact_size, deser_compact_size, hash160
from serializations import CTxIn, CTxInWitness, CTxOut, ser_string, COutPoint
from serializations import ser_sig_der, uint256_from_str, ser_push_data
from serializations import SIGHASH_ALL, SIGHASH_SINGLE, SIGHASH_NONE, SIGHASH_ANYONECANPAY
from serializations import ALL_SIGHASH_FLAGS, SIGHASH_DEFAULT
from opcodes import OP_CHECKMULTISIG, OP_RETURN
from glob import settings
from precomp_tag_hash import TAP_TWEAK_H, TAP_SIGHASH_H
from desc_utils import MusigKey, MUSIG_CHAIN_CODE
from wif import init_wif_store
from public_constants import (
PSBT_GLOBAL_UNSIGNED_TX, PSBT_GLOBAL_XPUB, PSBT_IN_NON_WITNESS_UTXO, PSBT_IN_WITNESS_UTXO,
PSBT_IN_PARTIAL_SIG, PSBT_IN_SIGHASH_TYPE, PSBT_IN_REDEEM_SCRIPT,
PSBT_IN_WITNESS_SCRIPT, PSBT_IN_BIP32_DERIVATION, PSBT_IN_FINAL_SCRIPTSIG,
PSBT_IN_FINAL_SCRIPTWITNESS, PSBT_OUT_REDEEM_SCRIPT, PSBT_OUT_WITNESS_SCRIPT,
PSBT_OUT_BIP32_DERIVATION, PSBT_OUT_TAP_BIP32_DERIVATION, PSBT_OUT_TAP_INTERNAL_KEY,
PSBT_IN_TAP_BIP32_DERIVATION, PSBT_IN_TAP_INTERNAL_KEY, PSBT_IN_TAP_KEY_SIG, PSBT_OUT_TAP_TREE,
PSBT_IN_TAP_MERKLE_ROOT, PSBT_IN_TAP_LEAF_SCRIPT, PSBT_IN_TAP_SCRIPT_SIG,
TAPROOT_LEAF_TAPSCRIPT,
PSBT_OUT_SCRIPT, PSBT_OUT_AMOUNT, PSBT_GLOBAL_VERSION,
PSBT_GLOBAL_TX_MODIFIABLE, PSBT_GLOBAL_OUTPUT_COUNT, PSBT_GLOBAL_INPUT_COUNT,
PSBT_GLOBAL_FALLBACK_LOCKTIME, PSBT_GLOBAL_TX_VERSION, PSBT_IN_PREVIOUS_TXID,
PSBT_IN_OUTPUT_INDEX, PSBT_IN_SEQUENCE, PSBT_IN_REQUIRED_TIME_LOCKTIME,
PSBT_IN_REQUIRED_HEIGHT_LOCKTIME, MAX_SIGNERS,
PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS, PSBT_IN_MUSIG2_PUB_NONCE, PSBT_IN_MUSIG2_PARTIAL_SIG,
PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS,
AF_P2WSH, AF_P2WSH_P2SH, AF_P2SH, AF_P2TR, AF_P2WPKH, AF_CLASSIC, AF_P2WPKH_P2SH,
AFC_SEGWIT, AF_BARE_PK
)
psbt_tmp256 = bytearray(256)
# transaction version error
TX_VER_ERR = "bad txn version"
# PSBT proprietary keytype
PSBT_PROPRIETARY = const(0xFC)
# PSBT proprietary identifier for Coinkite applications
PSBT_PROP_CK_ID = b"COINKITE"
# PSBT proprietary subtype for attestation entries
PSBT_ATTESTATION_SUBTYPE = const(0)
# Max miner's fee, as percentage of output value, that we will allow to be signed.
# Amounts over 5% are warned regardless.
DEFAULT_MAX_FEE_PERCENTAGE = const(10)
# print some things, sometimes
DEBUG = ckcc.is_simulator()
MUSIG_SESSION_CACHE = {}
class HashNDump:
def __init__(self, d=None):
self.rv = sha256()
print('Hashing: ', end='')
if d:
self.update(d)
def update(self, d):
print(b2a_hex(d), end=' ')
self.rv.update(d)
def digest(self):
print(' END')
return self.rv.digest()
def seq_to_str(seq):
# take a set or list of numbers and show a tidy list in order.
return ', '.join(str(i) for i in sorted(seq))
def _skip_n_objs(fd, n, cls):
# skip N sized objects in the stream, for example a vectors of CTxIns
# - returns starting position
if cls == 'CTxIn':
# output point(hash, n) + script sig + locktime
pat = [32+4, None, 4]
elif cls == 'CTxOut':
# nValue + Script
pat = [8, None]
else:
raise ValueError(cls)
rv = fd.tell()
for i in range(n):
for p in pat:
if p is None:
# variable-length part
sz = deser_compact_size(fd)
fd.seek(sz, 1)
else:
fd.seek(p, 1)
return rv
def disassemble_multisig_mn(redeem_script):
# pull out just M and N from script. Simple, faster, no memory.
if not redeem_script or (redeem_script[-1] != OP_CHECKMULTISIG):
return None, None
M = redeem_script[0] - 80
N = redeem_script[-2] - 80
return M, N
def calc_txid(fd, poslen, body_poslen=None):
# Given the (pos,len) of a transaction in a file, return the txid for that txn.
# - doesn't validate data
# - does detect witness txn vs. old style
# - simple double-sha256() if old style txn, otherwise witness data must be carefully skipped
# see if witness encoding in effect
fd.seek(poslen[0])
txn_version, marker, flags = unpack("<iBB", fd.read(6))
has_witness = (marker == 0 and flags != 0x0)
if not has_witness:
# txn does not have witness data, so txid==wtxix
return get_hash256(fd, poslen)
rv = sha256()
# de/reserialize much of the txn -- but not the witness data
rv.update(pack("<i", txn_version))
if body_poslen is None:
body_start = fd.tell()
# determine how long ins + outs are...
num_in = deser_compact_size(fd)
_skip_n_objs(fd, num_in, 'CTxIn')
num_out = deser_compact_size(fd)
_skip_n_objs(fd, num_out, 'CTxOut')
body_poslen = (body_start, fd.tell() - body_start)
# hash the bulk of txn
get_hash256(fd, body_poslen, hasher=rv)
# assume last 4 bytes are the lock_time
fd.seek(sum(poslen) - 4)
rv.update(fd.read(4))
return ngu.hash.sha256s(rv.digest())
def get_hash256(fd, poslen, hasher=None):
# return the double-sha256 of a value, without loading it into memory
# - if hasher provided, just updates over region of file (not a sha256d)
pos, ll = poslen
rv = hasher or sha256()
tmp = bytearray(min(256, ll))
fd.seek(pos)
while ll:
here = fd.readinto(tmp)
if not here:
raise ValueError
if here > ll:
here = ll
rv.update(memoryview(tmp)[0:here])
ll -= here
if hasher:
return
return ngu.hash.sha256s(rv.digest())
def decode_prop_key(key):
# decodes a proprietary (0xFC) key and breaks it down into:
# - identifier
# - subtype
# - keydata
with BytesIO(key) as fd:
identifier_len = deser_compact_size(fd)
identifier = fd.read(identifier_len)
subtype = deser_compact_size(fd)
keydata = fd.read()
return identifier, subtype, keydata
def encode_prop_key(identifier, subtype, keydata = b''):
# encodes a proprietary (0xFC) key into bytes
key = b''
key += ser_compact_size(len(identifier))
key += identifier
key += ser_compact_size(subtype)
key += keydata
return key
class psbtProxy:
# store offsets to values, but track the keys in-memory.
short_values = ()
no_keys = ()
# these fields will return None but are not stored unless a value is set
blank_flds = ('unknown',)
def __init__(self):
self.fd = None
def __getattr__(self, nm):
if nm in self.blank_flds:
return None
raise AttributeError(nm)
def parse(self, fd):
self.fd = fd
while 1:
ks = deser_compact_size(fd)
if ks is None: break
if ks == 0: break
key_pos = fd.tell() + 1 # first element is ktype
key = fd.read(ks)
vs = deser_compact_size(fd)
assert vs is not None, 'eof'
kt = key[0]
if kt in self.no_keys:
assert len(key) == 1 # not expecting key
# storing offset and length only! Mostly.
if kt in self.short_values:
actual = fd.read(vs)
self.store(kt, bytes(key), actual)
else:
# skip actual data for now
# TODO: could this be stored more compactly?
proxy = (fd.tell(), vs)
fd.seek(vs, 1)
# store just coords for both key & val
if kt == PSBT_PROPRIETARY:
ident, subtype, _ = decode_prop_key(key[1:])
# examine only Coinkite proprietary keys
if (ident == PSBT_PROP_CK_ID) and (subtype == PSBT_ATTESTATION_SUBTYPE):
# prop key for attestation does not have keydata because the
# value is a recoverable signature (already contains pubkey)
# just save what we can handle
self.attestation = proxy
self.store(kt, (key_pos, ks-1), proxy)
def coord_write(self, out_fd, val, ktype=None):
pos, ll = val
if ktype is None:
out_fd.write(ser_compact_size(ll))
else:
out_fd.write(ser_compact_size(ll+1))
out_fd.write(bytes([ktype]))
self.fd.seek(pos)
while ll:
t = self.fd.read(min(64, ll))
out_fd.write(t)
ll -= len(t)
def write(self, out_fd, ktype, val, key=b''):
# serialize helper: write w/ size and key byte
if isinstance(key, tuple):
self.coord_write(out_fd, key, ktype)
else:
out_fd.write(ser_compact_size(1 + len(key)))
out_fd.write(bytes([ktype]) + key)
if isinstance(val, tuple):
if ktype in (PSBT_IN_TAP_BIP32_DERIVATION, PSBT_OUT_TAP_BIP32_DERIVATION):
assert len(val) == 3
val = val[:-1] # ignore last element which is just (pos, len) of xfp+pth (after leaf hashes)
self.coord_write(out_fd, val)
else:
out_fd.write(ser_compact_size(len(val)))
out_fd.write(val)
def get(self, val):
# get the raw bytes for a value.
pos, ll = val
self.fd.seek(pos)
return self.fd.read(ll)
def parse_xfp_path(self, coords):
# coords are expected to be value from subpaths or taproot subpaths
return list(unpack_from('<%dI' % (coords[1] // 4), self.get(coords)))
def handle_zero_xfp(self, xfp_path, my_xfp, parent=None):
# Tricky & Useful: if xfp of zero is observed in file, assume that's a
# placeholder for my XFP value. Replace on the fly. Great when master
# XFP is unknown because PSBT built from derived XPUB only. Also privacy.
if xfp_path[0] == 0:
xfp_path[0] = my_xfp
if parent is not None:
if not any(True for k, _ in parent.warnings if 'XFP' in k):
parent.warnings.append(('Zero XFP',
'Assuming XFP of zero should be replaced by correct XFP'))
return xfp_path
def parse_taproot_subpaths(self, my_xfp, parent, cosign_xfp=None):
my_sp_idxs = []
ik_idxs = []
parsed_subpaths = OrderedDict()
for i in range(len(self.taproot_subpaths)):
key, val = self.taproot_subpaths[i]
assert key[1] == 32 # "PSBT_IN_TAP_BIP32_DERIVATION xonly-pubkey length != 32"
xonly_pk = self.get(key)
pos, length = val
end_pos = pos + length
self.fd.seek(pos)
leaf_hash_len = deser_compact_size(self.fd)
if leaf_hash_len:
self.fd.seek(32*leaf_hash_len, 1)
else:
ik_idxs.append(i)
curr_pos = self.fd.tell()
# this position is where actual xfp+path starts
# save it for faster access
to_read = end_pos - curr_pos
self.taproot_subpaths[i] = (key, (val[0], val[1], (curr_pos, to_read)))
# internal key is allowed to go from master
# unspendable path can be just a bare xonly pubkey
allow_master = True if not leaf_hash_len else False
validate_derivation_path_length(to_read, allow_master=allow_master)
v = self.fd.read(to_read)
here = list(unpack_from('<%dI' % (to_read // 4), v))
here = self.handle_zero_xfp(here, my_xfp, parent)
parsed_subpaths[xonly_pk] = [leaf_hash_len] + here
if (here[0] == my_xfp) or (here[0] == cosign_xfp) or parent.key_in_wif_store(xonly_pk):
my_sp_idxs.append(i)
if my_sp_idxs:
self.sp_idxs = my_sp_idxs
if ik_idxs:
self.ik_idx = ik_idxs
return parsed_subpaths
def parse_non_taproot_subpaths(self, my_xfp, parent, cosign_xfp=None):
parsed_subpaths = OrderedDict()
my_sp_idxs = []
for i, (key, val) in enumerate(self.subpaths):
# len pubkey 33 + 1 byte PSBT keys specifier
assert key[1] in {33, 65}, "hdpath pubkey len"
pk = self.get(key)
if len(pk) == 33:
assert pk[0] in {0x02, 0x03}, "uncompressed pubkey"
validate_derivation_path_length(val[1])
# promote to a list of ints
here = self.parse_xfp_path(val)
here = self.handle_zero_xfp(here, my_xfp, parent)
parsed_subpaths[pk] = here
if (here[0] == my_xfp) or (here[0] == cosign_xfp) or parent.key_in_wif_store(pk):
my_sp_idxs.append(i)
# else:
# Address that isn't based on my seed; might be another leg in a p2sh,
# or an input we're not supposed to be able to sign... and that's okay.
if my_sp_idxs:
self.sp_idxs = my_sp_idxs
return parsed_subpaths
def parse_subpaths(self, my_xfp, parent, cosign_xfp=None):
# - creates dictionary: pubkey => [xfp, *path] (self.subpaths)
# - creates dictionary: pubkey => [leaf_hash_list, xfp, *path] (self.taproot_subpaths)
if self.taproot_subpaths:
return self.parse_taproot_subpaths(my_xfp, parent, cosign_xfp)
elif self.subpaths:
return self.parse_non_taproot_subpaths(my_xfp, parent, cosign_xfp)
#return None in/output does not have any key-path info
# Track details of each output of PSBT
#
class psbtOutputProxy(psbtProxy):
no_keys = { PSBT_OUT_REDEEM_SCRIPT, PSBT_OUT_WITNESS_SCRIPT, PSBT_OUT_TAP_INTERNAL_KEY, PSBT_OUT_TAP_TREE }
blank_flds = ('unknown', 'subpaths', 'redeem_script', 'witness_script', 'sp_idxs',
'is_change', 'amount', 'script', 'attestation', 'proprietary',
'taproot_internal_key', 'taproot_subpaths', 'taproot_tree', 'ik_idx',
'musig_pubkeys')
def __init__(self, fd, idx):
super().__init__()
# things we track
#self.subpaths = None # a dictionary if non-empty
#self.taproot_subpaths = None # a dictionary if non-empty
#self.taproot_internal_key = None
#self.taproot_tree = None
#self.ik_idx = None # index of taproot internal key in taproot_subpaths
#self.redeem_script = None
#self.witness_script = None
#self.script = None
#self.amount = None
#self.musig_pubkeys = None
# this flag is set when we are assuming output will be change (same wallet)
#self.is_change = False
self.parse(fd)
# not needed
# def parse_taproot_tree(self):
# length = self.taproot_tree[1]
#
# res = []
# while length:
# tree = BytesIO(self.get(self.taproot_tree))
# depth = tree.read(1)
# leaf_version = tree.read(1)[0]
# assert (leaf_version & ~TAPROOT_LEAF_MASK) == 0
# script_len, nb = deser_compact_size(tree, ret_num_bytes=True)
# script = tree.read(script_len)
# res.append((depth, leaf_version, script))
# length -= (2 + nb + script_len)
#
# return res
def store(self, kt, key, val):
# do not forget that key[0] includes kt (type)
if kt == PSBT_OUT_BIP32_DERIVATION:
if not self.subpaths:
self.subpaths = []
self.subpaths.append((key,val))
elif kt == PSBT_OUT_REDEEM_SCRIPT:
self.redeem_script = val
elif kt == PSBT_OUT_WITNESS_SCRIPT:
self.witness_script = val
elif kt == PSBT_OUT_SCRIPT:
self.script = val
elif kt == PSBT_OUT_AMOUNT:
self.amount = val
elif kt == PSBT_PROPRIETARY:
self.proprietary = self.proprietary or []
self.proprietary.append((key, val))
elif kt == PSBT_OUT_TAP_INTERNAL_KEY:
self.taproot_internal_key = val
elif kt == PSBT_OUT_TAP_BIP32_DERIVATION:
self.taproot_subpaths = self.taproot_subpaths or []
self.taproot_subpaths.append((key, val))
elif kt == PSBT_OUT_TAP_TREE:
self.taproot_tree = val
elif kt == PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS:
self.musig_pubkeys = self.musig_pubkeys or []
self.musig_pubkeys.append((key, val))
else:
self.unknown = self.unknown or []
pos, length = key
self.unknown.append(((pos-1, length+1), val))
def serialize(self, out_fd, is_v2):
wr = lambda *a: self.write(out_fd, *a)
if self.subpaths:
for k, v in self.subpaths:
wr(PSBT_OUT_BIP32_DERIVATION, v, k)
if self.redeem_script:
wr(PSBT_OUT_REDEEM_SCRIPT, self.redeem_script)
if self.witness_script:
wr(PSBT_OUT_WITNESS_SCRIPT, self.witness_script)
if self.taproot_internal_key:
wr(PSBT_OUT_TAP_INTERNAL_KEY, self.taproot_internal_key)
if self.taproot_subpaths:
for k, v in self.taproot_subpaths:
wr(PSBT_OUT_TAP_BIP32_DERIVATION, v, k)
if self.taproot_tree:
wr(PSBT_OUT_TAP_TREE, self.taproot_tree)
if self.musig_pubkeys:
for k, v in self.musig_pubkeys:
wr(PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS, v, k)
if is_v2:
wr(PSBT_OUT_SCRIPT, self.script)
wr(PSBT_OUT_AMOUNT, self.amount)
if self.proprietary:
for k, v in self.proprietary:
wr(PSBT_PROPRIETARY, v, k)
if self.unknown:
for k, v in self.unknown:
wr(None, v, k)
def determine_my_change(self, out_idx, txo, parsed_subpaths, parent):
# Do things make sense for this output?
# NOTE: We might think it's a change output just because the PSBT
# creator has given us a key path. However, we must be **very**
# careful and fully validate all the details.
# - no output info is needed, in general, so
# any output info provided better be right, or fail as "fraud"
# - full key derivation and validation is done during signing, and critical.
# - we raise fraud alarms, since these are not innocent errors
# - must match expected address for this output, coming from unsigned txn
af, addr_or_pubkey = txo.get_address()
if (not self.sp_idxs) or (af in [OP_RETURN, None]):
# num_ours == 0
# - not considered fraud because other signers looking at PSBT may have them
# - user will see them as normal outputs, which they are from our PoV.
# OP_RETURN
# - nothing we can do with anchor outputs
# UNKNOWN
# - scripts that we do not understand
return af
msc = parent.active_miniscript
if msc and MiniScriptWallet.disable_checks:
# Without validation, we have to assume all outputs
# will be taken from us, and are not really change.
return af
# certain short-cuts
if msc:
if af in [AF_CLASSIC, AF_P2WPKH, AF_BARE_PK]:
# signing with miniscript wallet - single sig outputs definitely not change
return af
elif parent.active_singlesig and (af == AF_P2WSH):
# we are signing single sig inputs - p2wsh is def not a change
return af
def fraud(idx, af, err=""):
raise FraudulentChangeOutput(idx, "%s change output is fraudulent\n\n%s" % (
AF_TO_STR_AF[af], err
))
if af == AF_BARE_PK:
# output is compressed public key (not a hash, much less common)
# uncompressed public keys not supported!
assert len(addr_or_pubkey) == 33
assert len(parsed_subpaths) == 1
target, = parsed_subpaths.keys()
elif af in (AF_CLASSIC, AF_P2WPKH):
# P2PKH & P2WPKH (public key has, whether witness v0 or legacy)
# input is hash160 of a single public key
assert len(addr_or_pubkey) == 20
assert len(parsed_subpaths) == 1
target, = parsed_subpaths.keys()
target = hash160(target)
elif af in (AF_P2SH, AF_P2WSH): # both p2sh & p2wsh covered here
if msc:
# scriptPubkey can be compared against script that we build
# if exact match change if not - not change
# no need for redeem/witness script
# for instance liana & core do not provide witness/redeem
try:
xfp_paths = list(parsed_subpaths.values())
# if subpaths do not match, it is not desired wallet - so no change
# but also not a fraud
if msc.matching_subpaths(xfp_paths):
msc.validate_script_pubkey(txo.scriptPubKey, xfp_paths)
self.is_change = True
except AssertionError as e:
# sys.print_exception(e)
fraud(out_idx, af, e)
return af
# we do not have active miniscript - must be single sig otherwise, not a change
if len(parsed_subpaths) == 1 and (af == AF_P2SH):
expect_pubkey, = parsed_subpaths.keys()
target_spk, _ = chains.current_chain().script_pubkey(AF_P2WPKH_P2SH,
pubkey=expect_pubkey)
af = AF_P2WPKH_P2SH
if txo.scriptPubKey != target_spk:
fraud(out_idx, af, "spk mismatch")
# it's actually segwit p2wpkh inside p2sh
target = target_spk[2:-1]
else:
# done, not a change, subpaths > 1 or p2wsh (and not active miniscript)
return af
elif af == AF_P2TR:
if msc:
try:
xfp_paths = [v[1:] for v in parsed_subpaths.values()]
if msc.matching_subpaths(xfp_paths):
msc.validate_script_pubkey(txo.scriptPubKey, xfp_paths)
self.is_change = True
except AssertionError as e:
fraud(out_idx, af, e)
return af
if len(parsed_subpaths) == 1:
expect_pubkey, = parsed_subpaths.keys()
target = taptweak(expect_pubkey)
else:
# done, not a change, subpaths > 1 (and not active miniscript)
return af
# only basic single signature, non-miniscript scripts get here
assert parent.active_singlesig
if addr_or_pubkey != target:
fraud(out_idx, af)
# We will check pubkey value at the last second, during signing.
self.is_change = True
return af
# Track details of each input of PSBT
#
class psbtInputProxy(psbtProxy):
# just need to store a simple number for these
short_values = { PSBT_IN_SIGHASH_TYPE }
# only part-sigs have a key to be stored.
no_keys = {PSBT_IN_NON_WITNESS_UTXO, PSBT_IN_WITNESS_UTXO, PSBT_IN_SIGHASH_TYPE,
PSBT_IN_REDEEM_SCRIPT, PSBT_IN_WITNESS_SCRIPT, PSBT_IN_FINAL_SCRIPTSIG,
PSBT_IN_FINAL_SCRIPTWITNESS,PSBT_IN_TAP_KEY_SIG,
PSBT_IN_TAP_INTERNAL_KEY, PSBT_IN_TAP_MERKLE_ROOT}
blank_flds = (
'unknown', 'witness_utxo', 'sighash', 'redeem_script', 'witness_script', 'sp_idxs',
'fully_signed', 'af', 'is_miniscript', "subpaths", 'utxo', 'utxo_spk',
'amount', 'previous_txid', 'part_sigs', 'added_sigs', 'prevout_idx', 'sequence',
'req_time_locktime', 'req_height_locktime',
'taproot_merkle_root', 'taproot_script_sigs', 'taproot_scripts',
'taproot_subpaths', 'taproot_internal_key', 'taproot_key_sig', 'tr_added_sigs',
'ik_idx', 'musig_pubkeys', 'musig_pubnonces', 'musig_part_sigs', 'musig_agg_idx',
'musig_added_pubnonces', 'musig_added_sigs'
)
def __init__(self, fd, idx):
super().__init__()
#self.utxo = None
#self.witness_utxo = None
#self.part_sigs = []
#self.added_sigs = [] # signatures that we added (current siging session)
#self.sighash = None
#self.subpaths = [] # will be empty if taproot
#self.redeem_script = None
#self.witness_script = None
# Non-zero if one or more of our signing keys involved in input
#self.sp_idxs = list of indexes leading to our key in self.subpaths
# things we've learned
#self.fully_signed = False
# we can't really learn this until we take apart the UTXO's scriptPubKey
#self.af = None # address format aka. script type
#self.amount = None
#self.utxo_spk = None # scriptPubKey for input utxo
# === will be empty if non-taproot ===
# self.taproot_subpaths = {}
# self.taproot_internal_key = None
# self.taproot_key_sig = None
# self.taproot_merkle_root = None
# self.taproot_script_sigs = None
# self.taproot_scripts = None
# self.ik_idx = None # index of taproot internal key in taproot_subpaths
# ===
#self.previous_txid = None
#self.prevout_idx = None
#self.sequence = None
#self.req_time_locktime = None
#self.req_height_locktime = None
# === musig ===
#self.musig_pubkeys = None
#self.musig_pubnonces = None
#self.musig_part_sigs = None
self.parse(fd)
@property
def is_segwit(self):
return self.af & AFC_SEGWIT
@property
def is_musig(self):
return bool(self.musig_pubkeys or self.musig_pubnonces or self.musig_part_sigs)
def get_taproot_script_sigs(self):
# returns set of (xonly, script) provided via PSBT_IN_TAP_SCRIPT_SIG
# we do not parse control blocks (k) not needed
parsed_taproot_script_sigs = set()
for k, v in self.taproot_script_sigs or []:
key = self.get(k)
xonly, script_hash = key[:32], key[32:]
parsed_taproot_script_sigs.add((xonly, script_hash))
return parsed_taproot_script_sigs
def get_taproot_scripts(self):
# returns set of scripts provided via PSBT_IN_TAP_LEAF_SCRIPT
# we do not parse control blocks (k) not needed
t_scr = {}
for k, v in self.taproot_scripts or []:
script = self.get(v)
t_scr[script[:-1]] = script[-1] # only script, and script version
return t_scr
def get_musig_pubkeys(self):
parsed_musig_pubkeys = {}
for k, v in self.musig_pubkeys or []:
key = self.get(k)
pubkeys = self.get(v)
pk_list = []
for i in range(0, len(pubkeys), 33):
pk_list.append(pubkeys[i:i+33])
parsed_musig_pubkeys[key] = pk_list
return parsed_musig_pubkeys
def parse_musig_composite_key(self, key_coords):
# helper function to parse key from:
# * PSBT_IN_MUSIG2_PUB_NONCE
# * PSBT_IN_MUSIG2_PARTIAL_SIG
key = self.get(key_coords)
return key[:33], key[33:66], key[66:]
def get_musig_pubnonces(self):
parsed_musig_pubnonces = {}
for k, v in self.musig_pubnonces or []:
# participant pubkey, aggregate key, tapleaf hash
pk, ak, tlh = self.parse_musig_composite_key(k)
pubnonce = self.get(v)
parsed_musig_pubnonces[(pk, ak, tlh)] = pubnonce
return parsed_musig_pubnonces
def get_musig_part_sigs(self):
parsed_musig_part_sigs = {}
for k, v in self.musig_part_sigs or []:
# participant pubkey, aggregate key, tapleaf hash
pk, ak, tlh = self.parse_musig_composite_key(k)
sig = self.get(v)
parsed_musig_part_sigs[(pk, ak, tlh)] = sig
return parsed_musig_part_sigs
def get_tr_der_coords_by_key(self, target_key):
if not self.taproot_subpaths:
return None
if len(target_key) == 33:
# taproot subpaths only contain xonly keys
# yet function parameter 'target_key' may be classic compressed pubkey
# get rid of first bytes (containing parity bit)
target_key = target_key[1:]
sp = None
for k, v in self.taproot_subpaths:
xonly = self.get(k)
if target_key == xonly:
sp = v[2]
break
return sp
def has_relative_timelock(self, txin):
# https://github.com/bitcoin/bips/blob/master/bip-0068.mediawiki
SEQUENCE_LOCKTIME_DISABLE_FLAG = (1 << 31)
SEQUENCE_LOCKTIME_TYPE_FLAG = (1 << 22)
SEQUENCE_LOCKTIME_MASK = 0x0000ffff
SEQUENCE_LOCKTIME_GRANULARITY = 9
is_timebased = False
if txin.nSequence & SEQUENCE_LOCKTIME_DISABLE_FLAG:
# RTL disabled
return
if txin.nSequence & SEQUENCE_LOCKTIME_TYPE_FLAG:
# Time-based relative lock-time
is_timebased = True
res = (txin.nSequence & SEQUENCE_LOCKTIME_MASK) << SEQUENCE_LOCKTIME_GRANULARITY
else:
# Block height relative lock-time
res = txin.nSequence & SEQUENCE_LOCKTIME_MASK
if res == 0:
# any locktime that is zero, regardless of MPT or blocks
# is always immediately spendable
return
return is_timebased, res
def handle_none_sighash(self):
if self.sighash is None:
self.sighash = SIGHASH_DEFAULT if self.taproot_subpaths else SIGHASH_ALL
def has_utxo(self):
# do we have a copy of the corresponding UTXO?
return bool(self.utxo) or bool(self.witness_utxo)
def guess_multisig_addr_fmt(self):
# based on provided input scripts (witness/redeem)
if self.witness_script and not self.redeem_script:
return AF_P2WSH
elif self.witness_script and self.redeem_script:
return AF_P2WSH_P2SH
else:
return AF_P2SH
def get_utxo(self, idx):
# Load up the TxOut for specific output of the input txn associated with this in PSBT
# Aka. the "spendable" for this input #.
# - preserve the file pointer
# - nValue needed for total_value_in, but all fields needed for signing
#
fd = self.fd
old_pos = fd.tell()
if self.witness_utxo:
# Going forward? Just what we will witness; no other junk
# - prefer this format, altho does that imply segwit txn must be generated?
# - I don't know why we wouldn't always use this
# - once we use this partial utxo data, we must create witness data out
fd.seek(self.witness_utxo[0])
utxo = CTxOut()
utxo.deserialize(fd)
fd.seek(old_pos)
return utxo
assert self.utxo, 'no utxo'
# skip over all the parts of the txn we don't care about, without
# fully parsing it... pull out a single TXO
fd.seek(self.utxo[0])
_, marker, flags = unpack("<iBB", fd.read(6))
wit_format = (marker == 0 and flags != 0x0)
if not wit_format:
# rewind back over marker+flags
fd.seek(-2, 1)
# How many ins? We accept zero here because utxo's inputs might have been
# trimmed to save space, and we have test cases like that.
num_in = deser_compact_size(fd)
_skip_n_objs(fd, num_in, 'CTxIn')
num_out = deser_compact_size(fd)
assert idx < num_out, "not enuf outs"
_skip_n_objs(fd, idx, 'CTxOut')
utxo = CTxOut()
utxo.deserialize(fd)
# ... followed by more outs, and maybe witness data, but we don't care ...
fd.seek(old_pos)
return utxo
def determine_my_signing_key(self, my_idx, addr_or_pubkey, my_xfp, psbt, parsed_subpaths, utxo):
# See what it takes to sign this particular input
# - type of script
# - which pubkey needed
# - also validates redeem_script when present
merkle_root = redeem_script = None
if self.af == OP_RETURN:
return
if self.af is None:
# If this is reached, we do not understand the output well
# enough to allow the user to authorize the spend, so fail hard.
raise FatalPSBTIssue('Unhandled scriptPubKey: ' + b2a_hex(addr_or_pubkey).decode())
if psbt.active_miniscript or psbt.active_singlesig:
# we have already set one of these - sow we can use some short-cuts
if psbt.active_miniscript and (self.af in (AF_CLASSIC, AF_P2WPKH, AF_BARE_PK)):
# signing with miniscript wallet - ignore single sig utxos
self.sp_idxs = None
return
elif psbt.active_singlesig and (self.af == AF_P2WSH):
# we are signing single sig inputs - ignore p2wsh utxos
self.sp_idxs = None
return
if self.af == AF_BARE_PK:
# input is single compressed public key (less common)
# uncompressed public keys not supported!
assert len(addr_or_pubkey) == 33
for i, pubkey in enumerate(parsed_subpaths):
if pubkey == addr_or_pubkey:
assert i == self.sp_idxs[0]
break
else:
# pubkey provided is just wrong vs. UTXO
raise FatalPSBTIssue('Input #%d: pubkey wrong' % my_idx)
elif self.af in (AF_CLASSIC, AF_P2WPKH):
# P2PKH & P2WPKH
# input is hash160 of a single public key
for i, pubkey in enumerate(parsed_subpaths):
if hash160(pubkey) == addr_or_pubkey:
assert i == self.sp_idxs[0]
break
else:
# none of the pubkeys provided hashes to that address
raise FatalPSBTIssue('Input #%d: pubkey vs. address wrong' % my_idx)
elif self.af in (AF_P2WSH, AF_P2SH):
# we must have the redeem script already (else fail)
ks = self.witness_script or self.redeem_script
if not ks:
raise FatalPSBTIssue("Missing redeem/witness script for input #%d" % my_idx)
redeem_script = self.get(ks)
native_v0 = (self.af == AF_P2WSH)
if not native_v0 and (len(redeem_script) == 22) and \
redeem_script[0] == 0 and redeem_script[1] == 20 and \
len(parsed_subpaths) == 1:
for i, pubkey in enumerate(parsed_subpaths):
target_spk, _ = chains.current_chain().script_pubkey(AF_P2WPKH_P2SH,
pubkey=pubkey)
if target_spk == utxo.scriptPubKey:
# it's actually segwit p2wpkh inside p2sh
self.af = AF_P2WPKH_P2SH
assert i == self.sp_idxs[0]
else:
# Assume we'll be signing with any key we know
# - but if partial sig already in place, ignore that one
self.is_miniscript = True
# values will always be coords for both pubkey and signature at this point
done_keys = set()
if self.part_sigs:
done_keys = {self.get(k) for k,_ in self.part_sigs}
for i, (pubkey, path) in enumerate(parsed_subpaths.items()):
if pubkey in done_keys:
# pubkey has already signed, so - do not sign again
if i in self.sp_idxs:
# remove from sp_idxs so we do not attempt to sign again
self.sp_idxs.remove(i)
elif (path[0] == my_xfp) or psbt.key_in_wif_store(pubkey):
# slight chance of dup xfps, so handle
assert i in self.sp_idxs
if self.witness_script and (not native_v0) and (self.redeem_script[1] == 34):
# bugfix
self.af = AF_P2WSH_P2SH
assert self.redeem_script[1] == 34
if self.af in (AF_P2WSH, AF_P2WSH_P2SH):
# for both P2WSH & P2SH-P2WSH
if not self.witness_script:
raise FatalPSBTIssue('Need witness script for input #%d' % my_idx)
elif self.af == AF_P2TR:
if len(parsed_subpaths) == 1:
# keyspend without a script path
assert self.taproot_merkle_root is None, "merkle_root should not be defined for simple keyspend"
assert self.ik_idx == [0]
xonly_pubkey, lhs_path = list(parsed_subpaths.items())[0]
lhs, path = lhs_path[0], lhs_path[1:]
assert not lhs, "LeafHashes have to be empty for internal key"
assert self.sp_idxs[0] == 0
assert taptweak(xonly_pubkey) == addr_or_pubkey
else:
self.is_miniscript = True
if self.taproot_merkle_root is not None:
merkle_root = self.get(self.taproot_merkle_root)
for i, (xonly_pubkey, lhs_path) in enumerate(parsed_subpaths.items()):
if i not in self.sp_idxs:
# # ignore keys that does not have correct xfp specified in PSBT
continue
if psbt.key_in_wif_store(xonly_pubkey):
assert i in self.sp_idxs
lhs, path = lhs_path[0], lhs_path[1:]
# assert merkle_root is not None, "Merkle root not defined"
if self.ik_idx and len(self.ik_idx) == 1 and self.ik_idx[0] == i:
assert not lhs
output_key = taptweak(xonly_pubkey, merkle_root)
if output_key == addr_or_pubkey:
# if we find a possibility to spend keypath (internal_key) - we do keypath
# even though script path is available
self.sp_idxs = [i]
break # done ignoring all other possibilities
else:
internal_key = self.get(self.taproot_internal_key)
output_pubkey = taptweak(internal_key, merkle_root)
assert addr_or_pubkey == output_pubkey
if self.is_miniscript:
if not self.sp_idxs: return
if psbt.active_singlesig:
# if we already considered single signature inputs for signing
# do not even consider to sign with miniscript wallet(s)
# maybe we removed
self.sp_idxs = None
return # required key is None
if self.af == AF_P2TR:
xfp_paths = [item[1:] for item in parsed_subpaths.values()]
else:
xfp_paths = list(parsed_subpaths.values())
if psbt.active_miniscript:
if not MiniScriptWallet.disable_checks:
if not psbt.active_miniscript.matching_subpaths(xfp_paths):
# not input from currently selected wallet
self.sp_idxs = None
return
else:
# if we do have actual script at hand, guess M/N for better matching
# basic multisig matching
M, N = disassemble_multisig_mn(redeem_script)
wal = MiniScriptWallet.find_match(xfp_paths, self.af, M, N)
if not wal:
# not an input from wallet that we have enrolled
self.sp_idxs = None
return
psbt.active_miniscript = wal
try:
# contains PSBT merkle root verification (if taproot)
if not MiniScriptWallet.disable_checks:
psbt.active_miniscript.validate_script_pubkey(self.utxo_spk, xfp_paths,
merkle_root)
except BaseException as e:
# sys.print_exception(e)
raise FatalPSBTIssue('Input #%d: %s\n\n' % (my_idx, e) + problem_file_line(e))
else:
# single signature utxo
if psbt.active_miniscript:
# complex wallet is active - so this is not for us to sign
self.sp_idxs = None
return
psbt.active_singlesig = True
def segwit_v0_scriptCode(self):
# only v0 segwit
# only needed for sighash
assert self.is_segwit and (self.af != AF_P2TR)
if self.af == AF_P2WPKH:
return b'\x19\x76\xa9\x14' + self.utxo_spk[2:2+20] + b'\x88\xac'
elif self.af == AF_P2WPKH_P2SH:
return b'\x19\x76\xa9\x14' + self.get(self.redeem_script)[2:22] + b'\x88\xac'
elif self.af in (AF_P2WSH, AF_P2WSH_P2SH):
# "scriptCode is witnessScript preceeded by a
# compactSize integer for the size of witnessScript"
return ser_string(self.get(self.witness_script))
def get_scriptSig(self):
if self.af in [AF_BARE_PK, AF_CLASSIC]:
return self.utxo_spk
elif self.af in (AF_P2SH, AF_P2WSH_P2SH, AF_P2WPKH_P2SH):
return self.get(self.redeem_script)
else:
return b""
def store(self, kt, key, val):
# Capture what we are interested in.
if kt == PSBT_IN_NON_WITNESS_UTXO:
self.utxo = val
elif kt == PSBT_IN_WITNESS_UTXO:
self.witness_utxo = val
elif kt == PSBT_IN_PARTIAL_SIG:
# taproot inputs do not have part sigs
# only populate the attribute if present
if not self.part_sigs:
self.part_sigs = []
# do not load anything (both key and val are coordinates)
# actual signatures (71 bytes) we do not need them until finalization
# public keys are enough for validation we will get them as needed
self.part_sigs.append((key, val))
elif kt == PSBT_IN_BIP32_DERIVATION:
if self.subpaths is None:
self.subpaths = []
self.subpaths.append((key, val))
elif kt == PSBT_IN_REDEEM_SCRIPT:
self.redeem_script = val
elif kt == PSBT_IN_WITNESS_SCRIPT:
self.witness_script = val
elif kt == PSBT_IN_SIGHASH_TYPE:
self.sighash = unpack('<I', val)[0]
elif kt == PSBT_IN_TAP_INTERNAL_KEY:
self.taproot_internal_key = val
elif kt == PSBT_IN_TAP_BIP32_DERIVATION:
if self.taproot_subpaths is None:
self.taproot_subpaths = []
self.taproot_subpaths.append((key, val))
elif kt == PSBT_IN_TAP_KEY_SIG:
self.taproot_key_sig = val
elif kt == PSBT_IN_TAP_MERKLE_ROOT:
self.taproot_merkle_root = val
elif kt == PSBT_IN_TAP_SCRIPT_SIG:
self.taproot_script_sigs = self.taproot_script_sigs or []
self.taproot_script_sigs.append((key, val))
elif kt == PSBT_IN_TAP_LEAF_SCRIPT:
self.taproot_scripts = self.taproot_scripts or []
self.taproot_scripts.append((key, val))
elif kt == PSBT_IN_PREVIOUS_TXID:
self.previous_txid = val
elif kt == PSBT_IN_OUTPUT_INDEX:
self.prevout_idx = val
elif kt == PSBT_IN_SEQUENCE:
self.sequence = unpack("<I", self.get(val))[0]
elif kt == PSBT_IN_REQUIRED_TIME_LOCKTIME:
self.req_time_locktime = unpack("<I", self.get(val))[0]
elif kt == PSBT_IN_REQUIRED_HEIGHT_LOCKTIME:
self.req_height_locktime = unpack("<I", self.get(val))[0]
elif kt == PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS:
self.musig_pubkeys = self.musig_pubkeys or []
self.musig_pubkeys.append((key, val))
elif kt == PSBT_IN_MUSIG2_PUB_NONCE:
self.musig_pubnonces = self.musig_pubnonces or []
self.musig_pubnonces.append((key, val))
elif kt == PSBT_IN_MUSIG2_PARTIAL_SIG:
self.musig_part_sigs = self.musig_part_sigs or []
self.musig_part_sigs.append((key, val))
else:
# including: PSBT_IN_FINAL_SCRIPTSIG, PSBT_IN_FINAL_SCRIPTWITNESS
self.unknown = self.unknown or []
pos, length = key
self.unknown.append(((pos - 1, length + 1), val))
def serialize(self, out_fd, is_v2):
# Output this input's values; might include signatures that weren't there before
wr = lambda *a: self.write(out_fd, *a)
if self.utxo:
wr(PSBT_IN_NON_WITNESS_UTXO, self.utxo)
if self.witness_utxo:
wr(PSBT_IN_WITNESS_UTXO, self.witness_utxo)
if self.part_sigs:
for pk, sig in self.part_sigs:
wr(PSBT_IN_PARTIAL_SIG, sig, pk)
if self.added_sigs:
for pk, sig in self.added_sigs:
wr(PSBT_IN_PARTIAL_SIG, sig, pk)
if self.taproot_key_sig:
wr(PSBT_IN_TAP_KEY_SIG, self.taproot_key_sig)
if self.sighash is not None:
wr(PSBT_IN_SIGHASH_TYPE, pack('<I', self.sighash))
if self.subpaths:
for k, v in self.subpaths:
wr(PSBT_IN_BIP32_DERIVATION, v, k)
if self.redeem_script:
wr(PSBT_IN_REDEEM_SCRIPT, self.redeem_script)
if self.witness_script:
wr(PSBT_IN_WITNESS_SCRIPT, self.witness_script)
if self.taproot_internal_key:
wr(PSBT_IN_TAP_INTERNAL_KEY, self.taproot_internal_key)
if self.taproot_subpaths:
for k, v in self.taproot_subpaths:
wr(PSBT_IN_TAP_BIP32_DERIVATION, v, k)
if self.taproot_merkle_root:
wr(PSBT_IN_TAP_MERKLE_ROOT, self.taproot_merkle_root)
if self.taproot_script_sigs:
for k, v in self.taproot_script_sigs:
wr(PSBT_IN_TAP_SCRIPT_SIG, v, k)
if self.tr_added_sigs:
for (xonly, leaf_hash), sig in self.tr_added_sigs.items():
wr(PSBT_IN_TAP_SCRIPT_SIG, sig, xonly + leaf_hash)
if self.taproot_scripts:
for k, v in self.taproot_scripts:
wr(PSBT_IN_TAP_LEAF_SCRIPT, v, k)
if self.musig_pubkeys:
for k, v in self.musig_pubkeys:
wr(PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS, v, k)
if self.musig_pubnonces:
for k, v in self.musig_pubnonces:
wr(PSBT_IN_MUSIG2_PUB_NONCE, v, k)
if self.musig_added_pubnonces:
for (pk, ak, lh), pubnonce in self.musig_added_pubnonces.items():
wr(PSBT_IN_MUSIG2_PUB_NONCE, pubnonce, pk + ak + lh)
if self.musig_part_sigs:
for k, v in self.musig_part_sigs:
wr(PSBT_IN_MUSIG2_PARTIAL_SIG, v, k)
if self.musig_added_sigs:
for (pk, ak, lh), v in self.musig_added_sigs.items():
wr(PSBT_IN_MUSIG2_PARTIAL_SIG, v, pk + ak + lh)
if is_v2:
wr(PSBT_IN_PREVIOUS_TXID, self.previous_txid)
wr(PSBT_IN_OUTPUT_INDEX, self.prevout_idx)
if self.sequence is not None:
wr(PSBT_IN_SEQUENCE, pack("<I", self.sequence))
if self.req_time_locktime is not None:
wr(PSBT_IN_REQUIRED_TIME_LOCKTIME, pack("<I", self.req_time_locktime))
if self.req_height_locktime is not None:
wr(PSBT_IN_REQUIRED_HEIGHT_LOCKTIME, pack("<I", self.req_height_locktime))
if self.unknown:
for k, v in self.unknown:
wr(None, v, k)
class psbtObject(psbtProxy):
"Just? parse and store"
short_values = { PSBT_GLOBAL_TX_MODIFIABLE }
no_keys = { PSBT_GLOBAL_UNSIGNED_TX }
blank_flds = ("hashPrevouts", "hashSequence", "hashOutputs", "hashValues", "hashScriptPubKeys",
"my_tr_in", "unknown")
def __init__(self):
super().__init__()
# global objects
self.version = None
self.txn = None
self.xpubs = [] # tuples(xfp_path, xpub)
self.my_xfp = settings.get('xfp', 0)
self.wif_store = init_wif_store()
# details that we discover as we go
self.inputs = None
self.outputs = None
self.had_witness = None
self.num_inputs = None
self.num_outputs = None
self.txn_modifiable = None
self.fallback_locktime = None
self.vin_start = None
self.vout_start = None
self.wit_start = None
self.txn_version = None
self._lock_time = None
self.total_value_out = None
self.total_value_in = None
# will be tru if number of change outputs equals to total number of outputs
self.consolidation_tx = False
# number of change outputs
self.num_change_outputs = None
self.total_change_value = None
# when signing segwit stuff, there is some re-use of hashes
# only if SIGHASH_ALL
# self.hashPrevouts = None
# self.hashSequence = None
# self.hashOutputs = None
# segwit v1
# self.hashValues = None
# self.hashScriptPubKeys = None
# self.my_tr_in = None # set to true if any taproot input is ours to sign
# this points to a Miniscript wallet, during operation
# - we are only supporting a single miniscript wallet during signing
self.active_miniscript = None
# - if we plan to sign signle signature inputs
self.active_singlesig = None
self.warnings = []
# not a warning just more info about tx
# presented in UX on confirm tx screen before warnings
self.ux_notes = []
# v1 vs v2 validation
self.is_v2 = False
self.has_gic = False # global input count
self.has_goc = False # global output count
self.has_gtv = False # global txn version
# musig related
self.session = None
self.allow_cache_store = False
# Proof of Reserves
self.por322 = False
self.por322_msg_hash = None
self.por322_msg_challenge = None
# tracks whether any signatures were added by us
# in musig world, we can only add nonce
self.sig_added = False
def key_in_wif_store(self, key):
# key -> public key (xonly or classic compressed)
# wif_store -> initialized wif store as in psbt class
# returns key as found in wif store
assert len(key) in [32, 33]
if len(key) == 32:
# taproot xonly key
if b"\x02" + key in self.wif_store:
return b"\x02" + key
elif b"\x03" + key in self.wif_store:
return b"\x03" + key
else:
if key in self.wif_store:
return key
return None
@property
def lock_time(self):
return (self._lock_time or self.fallback_locktime) or 0
def store(self, kt, key, val):
# capture the values we care about
if kt == PSBT_GLOBAL_UNSIGNED_TX:
self.txn = val
elif kt == PSBT_GLOBAL_XPUB:
# list of tuples(xfp_path, xpub)
self.xpubs.append((key, val))
assert len(self.xpubs) <= MAX_SIGNERS
elif kt == PSBT_GLOBAL_VERSION:
self.version = unpack("<I", self.get(val))[0]
elif kt == PSBT_GLOBAL_TX_VERSION:
self.txn_version = unpack("<i", self.get(val))[0]
self.has_gtv = True
elif kt == PSBT_GLOBAL_FALLBACK_LOCKTIME:
self.fallback_locktime = unpack("<I", self.get(val))[0]
elif kt == PSBT_GLOBAL_INPUT_COUNT:
self.num_inputs = deser_compact_size(BytesIO(self.get(val)))
self.has_gic = True
elif kt == PSBT_GLOBAL_OUTPUT_COUNT:
self.num_outputs = deser_compact_size(BytesIO(self.get(val)))
self.has_goc = True
elif kt == PSBT_GLOBAL_TX_MODIFIABLE:
# bytes of length 1 (tx modifiable in short_values)
assert len(val) == 1
self.txn_modifiable = val[0]
else:
self.unknown = self.unknown or []
pos, length = key
self.unknown.append(((pos - 1, length + 1), val))
def output_iter(self, start=0, stop=None):
# yield the txn's outputs: index, (CTxOut object) for each
if stop is None:
stop = self.num_outputs
if self.is_v2:
for idx in range(start, stop):
out = self.outputs[idx]
amount = unpack("<q", self.get(out.amount))[0]
tx_out = CTxOut(nValue=amount, scriptPubKey=self.get(out.script))
yield idx, tx_out
else:
assert self.vout_start is not None # must call input_iter/validate first
fd = self.fd
fd.seek(self.vout_start)
if start != 0:
_skip_n_objs(fd, start, 'CTxOut')
tx_out = CTxOut()
for idx in range(start, stop):
tx_out.deserialize(fd)
cont = fd.tell()
yield idx, tx_out
fd.seek(cont)
def parse_txn(self):
# Need to semi-parse in unsigned transaction.
# - learn number of ins/outs so rest of PSBT can be understood
# - also captures lots of position details
# - called right after globals section is read
fd = self.fd
old_pos = fd.tell()
fd.seek(self.txn[0])
# see serializations.py:CTransaction.deserialize()
# and BIP-144 ... we expect witness serialization, but
# don't force that
self.txn_version, marker, flags = unpack("<iBB", fd.read(6))
self.had_witness = (marker == 0 and flags != 0x0)
assert self.txn_version in {0,1,2,3}, TX_VER_ERR
if not self.had_witness:
# rewind back over marker+flags
fd.seek(-2, 1)
num_in = deser_compact_size(fd)
assert num_in > 0, "no ins?"
self.num_inputs = num_in
# all the ins are in sequence starting at this position
self.vin_start = _skip_n_objs(fd, num_in, 'CTxIn')
# next is outputs
self.num_outputs = deser_compact_size(fd)
self.vout_start = _skip_n_objs(fd, self.num_outputs, 'CTxOut')
end_pos = sum(self.txn)
# remainder is the witness data, and then the lock time
if self.had_witness:
# we'll need to come back to this pos if we
# want to read the witness data later.
self.wit_start = _skip_n_objs(fd, num_in, 'CTxInWitness')
# we are at end of outputs, and no witness data, so locktime is here
self._lock_time = unpack("<I", fd.read(4))[0]
assert fd.tell() == end_pos, 'txn read end wrong'
fd.seek(old_pos)
def input_iter(self, start=0, stop=None):
# Yield each of the txn's inputs, as a tuple:
#
# (index, CTxIn)
#
# - we also capture much data about the txn on the first pass thru here
#
if stop is None:
stop = self.num_inputs
if self.is_v2:
for idx in range(start, stop):
inp = self.inputs[idx]
prevout = COutPoint(uint256_from_str(self.get(inp.previous_txid)),
unpack("<I", self.get(inp.prevout_idx))[0])
sequence = inp.sequence if inp.sequence is not None else 0xffffffff
txin = CTxIn(outpoint=prevout, nSequence=sequence)
yield idx, txin
else:
fd = self.fd
assert self.vin_start
# stream out the inputs
fd.seek(self.vin_start)
if start != 0:
_skip_n_objs(fd, start, 'CTxIn')
txin = CTxIn()
for idx in range(start, stop):
txin.deserialize(fd)
cont = fd.tell()
yield idx, txin
fd.seek(cont)
def input_witness_iter(self):
# yield all the witness data, in order by input
if not self.had_witness:
# original txn had no witness data, so provide placeholder objs
for in_idx in range(self.num_inputs):
yield in_idx, CTxInWitness()
return
fd.seek(self.wit_start)
for idx in range(num_in):
wit = CTxInWitness()
wit.deserialize(fd)
cont = fd.tell()
yield idx, wit
fd.seek(cont)
def guess_M_of_N(self):
# Peek at the inputs to see if we can guess M/N value. Just takes
# first one it finds.
#
for i in self.inputs:
ks = i.witness_script or i.redeem_script
if not ks: continue
rs = i.get(ks)
if rs[-1] != OP_CHECKMULTISIG: continue
if not i.subpaths: continue # not ours
for _, val in i.subpaths:
if self.my_xfp == self.parse_xfp_path(val)[0]:
break
else:
# does not contain our key (master xfp) in subpaths
continue
M, N = disassemble_multisig_mn(rs)
# does not match PSBT_XPUBS length
if N != len(self.xpubs): continue
assert 1 <= M <= N <= MAX_SIGNERS
# guess address format also - based on scripts provided by PSBT provider
af = i.guess_multisig_addr_fmt()
return af, M, N
# not multisig, probably
return None, None, None
async def handle_xpubs(self):
# Lookup correct wallet based on xpubs in globals
# - only happens if they volunteered this 'extra' data
# - do not assume multisig
has_mine = 0
parsed_xpubs = []
for k,v in self.xpubs:
xp = self.get(k)
h = self.parse_xfp_path(v)
assert len(h) >= 1
parsed_xpubs.append((xp, h))
if h[0] == self.my_xfp:
has_mine += 1
if not has_mine:
raise FatalPSBTIssue('My XFP not involved')
if self.active_miniscript:
# user is going via wallet->Sign PSBT
# check XPUBs are correct
if not self.active_miniscript.disable_checks:
self.active_miniscript.validate_psbt_xpubs(parsed_xpubs)
return
# don't want to guess M if not needed, but we need it
af, M, N = self.guess_M_of_N()
if not N:
# not multisig, but we can still verify:
# - miniscript cannot be imported from PSBT (we lack descriptor in PSBT)
# - XFP should be one of ours (checked above).
# - too slow to re-derive it here, so nothing more to validate at this point
return
assert N == len(self.xpubs)
# Validate good match here. The xpubs must be exactly right, but
# we're going to use our own values from setup time anyway and not trusting
# new values without user interaction.
# Check:
# - chain codes match what we have stored already
# - pubkey vs. path will be checked later
# - xfp+path already checked above when selecting wallet
# Any issue here is a fraud attempt in some way, not innocent.
wal = MiniScriptWallet.find_match([i[1] for i in parsed_xpubs], af, M, N)
if wal:
# exact match (by xfp+deriv set) .. normal case
self.active_miniscript = wal
else:
trust_mode = MiniScriptWallet.get_trust_policy()
# already checked for existing import and wasn't found, so fail
if trust_mode == TRUST_VERIFY:
raise FatalPSBTIssue("XPUBs in PSBT do not match any existing wallet")
# Maybe create wallet, for today, forever, or fail, etc.
proposed = MiniScriptWallet.import_from_psbt(af, M, N, parsed_xpubs)
if trust_mode != TRUST_PSBT:
# do a complex UX sequence, which lets them save new wallet
from glob import hsm_active
if hsm_active:
raise FatalPSBTIssue("MS enroll not allowed in HSM mode")
approved = await proposed.confirm_import()
if not approved:
raise FatalPSBTIssue("Refused to import new wallet")
self.active_miniscript = proposed
# must have wallet at this point
assert self.active_miniscript
def ux_relative_timelocks(self, tb, bb):
# visualize 10 largest timelock to user
# when signing a tx
MAX_SHOW = 10
num_tb = len(tb)
num_bb = len(bb)
if (num_tb + num_bb) > MAX_SHOW:
# 10 from each is enough for us to have in memory
tb = sorted(tb, key=lambda item: item[1], reverse=True)[:10]
bb = sorted(bb, key=lambda item: item[1], reverse=True)[:10]
if (num_tb >= 5) and (num_bb >= 5):
# 5 biggest from each
tb = tb[:5]
bb = bb[:5]
else:
if num_tb < num_bb:
tb = tb[:num_tb]
bb = bb[:(MAX_SHOW - num_tb)]
else:
bb = bb[:num_bb]
tb = tb[:(MAX_SHOW - num_bb)]
if num_bb:
# Block height relative lock-time
if num_bb == 1:
idx, val = bb[0]
msg = "Input %d. has relative block height timelock of %d blocks\n" % (
idx, val
)
elif all(bb[0][1] == i[1] for i in bb):
msg = "%d inputs have relative block height timelock of %d blocks\n" % (
num_bb, bb[0][1]
)
else:
msg = "%d inputs have relative block height timelock." % num_bb
if num_bb > len(bb):
msg += " Showing only %d with highest values." % len(bb)
msg += "\n\n"
for idx, num_blocks in bb:
msg += " %d. %d blocks\n" % (idx, num_blocks)
self.ux_notes.append(("Block height RTL", msg))
if num_tb:
# Block height relative lock-time
if num_tb == 1:
idx, val = tb[0]
val = seconds2human_readable(val)
msg = "Input %d. has relative time-based timelock of:\n %s\n" % (
idx, val
)
elif all(tb[0][1] == i[1] for i in tb):
msg = "%d inputs have relative time-based timelock of:\n %s\n" % (
num_tb, seconds2human_readable(tb[0][1])
)
else:
msg = "%d inputs have relative time-based timelock." % num_tb
if num_tb > len(tb):
msg += " Showing only %d with highest values." % len(tb)
msg += "\n\n"
for idx, seconds in tb:
hr = seconds2human_readable(seconds)
msg += " %d. %s\n" % (idx, hr)
self.ux_notes.append(("Time-based RTL", msg))
def validate_unkonwn(self, obj, label):
# find duplicate unknown values in different PSBT parts
if not obj.unknown:
return
if len({self.get(k) for k,_ in obj.unknown}) < len(obj.unknown):
raise FatalPSBTIssue("Duplicate key. Key for unknown value"
" already provided in %s." % label)
def validate_musig_pubkeys(self, obj):
# for both input & output objects:
# * PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS
# * PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS
for k, v in obj.musig_pubkeys:
assert k[1] == 33 # compressed pubkey len 33
assert v[1] # list of pubkeys cannot be empty
assert (v[1] % 33 == 0) # each pubkey len 33
async def validate(self):
# Do a first pass over the txn. Raise assertions, be terse tho because
# these messages are rarely seen. These are syntax/fatal errors.
#
if self.version is not None:
# verision is provided in PSBT - take it as given
assert self.version in (0,2)
else:
# PSBT version is not defined
# global unsigned tx is only allowed in v0
self.version = 2 if self.txn is None else 0
self.is_v2 = self.version is not None and self.version >= 2
if self.is_v2:
assert self.has_gic, "v2 requires global input count"
assert self.has_goc, "v2 requires global output count"
assert self.has_gtv, "v2 requires global txn version"
assert self.txn is None, "v2 requires exclusion of global unsigned tx"
else:
assert not self.has_gic, "v0 requires exclusion of global input count"
assert not self.has_goc, "v0 requires exclusion of global output count"
assert not self.has_gtv, "v0 requires exclusion of global txn version"
assert self.txn, "v0 requires inclusion of global unsigned tx"
# smallest possible Proof of Reserves transaction has 61 bytes
assert self.txn[1] > 60, 'txn too short'
assert self.fallback_locktime is None, "v0 requires exclusion of global fallback locktime"
assert self.txn_modifiable is None, "v0 requires exclusion of global txn modifiable"
assert len(self.inputs) == self.num_inputs, 'ni mismatch'
assert self.num_outputs >= 1, 'need outputs'
self.validate_unkonwn(self, "global namespace")
inp_have_subpath = False
for i in self.inputs:
if i.subpaths or i.taproot_subpaths:
inp_have_subpath = True
if self.is_v2:
# v2 requires inclusion
assert i.prevout_idx is not None
assert i.previous_txid
if i.req_time_locktime is not None:
assert i.req_time_locktime >= NLOCK_IS_TIME
if i.req_height_locktime is not None:
assert 0 < i.req_height_locktime < NLOCK_IS_TIME
else:
# v0 requires exclusion
assert i.prevout_idx is None
assert i.previous_txid is None
assert i.sequence is None
assert i.req_time_locktime is None
assert i.req_height_locktime is None
if i.witness_script:
assert i.witness_script[1] >= 30
if i.redeem_script:
assert i.redeem_script[1] >= 22
if i.taproot_internal_key:
assert i.taproot_internal_key[1] == 32 # "PSBT_IN_TAP_INTERNAL_KEY length != 32"
if i.taproot_key_sig:
# "PSBT_IN_TAP_KEY_SIG length != 64 or 65"
assert i.taproot_key_sig[1] in (64, 65)
if i.part_sigs:
for k, v in i.part_sigs:
assert k[1] == 33
# valid signature can also be 60 bytes or less (needs grinding)
# 69 bytes - where both r & s are 31 bytes
# 73 -> high-s & high-r
assert v[1] <= 73, "DER sig len"
if i.taproot_script_sigs:
for k, v in i.taproot_script_sigs:
# PSBT_IN_TAP_SCRIPT_SIG + 32 bytes xonly pubkey + leafhash 32 bytes
assert k[1] == 64
# The 64 or 65 byte Schnorr signature for this pubkey and leaf combination
assert v[1] in (64, 65)
if i.taproot_scripts:
for k, v in i.taproot_scripts:
assert k[1] > 32 # "PSBT_IN_TAP_LEAF_SCRIPT control block is too short"
assert (k[1] - 1) % 32 == 0 # "PSBT_IN_TAP_LEAF_SCRIPT control block is not valid"
assert v[1] != 0 # "PSBT_IN_TAP_LEAF_SCRIPT cannot be empty"
if i.musig_pubkeys:
self.validate_musig_pubkeys(i)
if i.musig_pubnonces:
for k, v in i.musig_pubnonces:
assert k[1] in (66, 98) # PSBT_IN_MUSIG2_PUB_NONCE key is participant pubkey (33) + aggregate pubkey (33) + (optional) tapleaf hash (32)
assert v[1] == 66 # PSBT_IN_MUSIG2_PUB_NONCE value is pubnonce
if i.musig_part_sigs:
for k, v in i.musig_part_sigs:
assert k[1] in (66, 98) # PSBT_IN_MUSIG2_PARTIAL_SIG key is participant pubkey (33) + aggregate pubkey (33) + (optional) tapleaf hash (32)
assert v[1] == 32 # PSBT_IN_MUSIG2_PARTIAL_SIG value is partial signature
if i.sighash and (i.sighash not in ALL_SIGHASH_FLAGS):
raise FatalPSBTIssue("Unsupported sighash flag 0x%x" % i.sighash)
self.validate_unkonwn(i, "input")
null_data_op_return = False
for o in self.outputs:
if self.is_v2:
# v2 requires inclusion
assert o.amount
assert o.script
if o.amount == 0 and o.script == b'\x6a':
null_data_op_return = True
else:
# v0 requires exclusion
assert o.amount is None
assert o.script is None
if o.taproot_internal_key:
assert o.taproot_internal_key[1] == 32 # "PSBT_OUT_TAP_INTERNAL_KEY length != 32"
if o.musig_pubkeys:
self.validate_musig_pubkeys(o)
self.validate_unkonwn(o, "output")
if not self.is_v2 and (self.num_outputs == 1):
for idx, txo in self.output_iter():
if txo.nValue == 0 and txo.scriptPubKey == b'\x6a':
null_data_op_return = True
if null_data_op_return and (len(self.outputs) == 1):
self.por322 = True
if self.txn_version == 0:
# only allow txn version 0 for Proof of Reserves txn (BIP-322)
assert self.por322, TX_VER_ERR
if not inp_have_subpath:
# Can happen w/ Electrum in watch-mode on XPUB. It doesn't know XFP and
# so doesn't insert that into PSBT.
# or PSBT provider forgot to include subpaths
raise FatalPSBTIssue('PSBT inputs do not contain any key path information.')
# if multisig xpub details provided, they better be right and/or offer import
if self.xpubs:
await self.handle_xpubs()
if DEBUG:
print("PSBT: %d inputs, %d output" % (self.num_inputs, self.num_outputs))
def consider_outputs(self, len_pths, hard_p, prefix_pths, idx_max, cosign_xfp=None):
from glob import dis
# scan ouputs:
# - is it a change address, defined by redeem script (p2sh) or key we know is ours
# - mark change outputs, so perhaps we don't show them to users
total_out = 0
total_change = 0
num_op_return = 0
num_op_return_size = 0
num_unknown_scripts = 0
zero_val_outs = 0 # only those that are not OP_RETURN are considered
self.num_change_outputs = 0
validate_inp_pths = False
path_len = None
max_gap = idx_max + 200
# We aren't seeing shared input path lengths.
# They are probably doing weird stuff, so leave them alone
# and do not validate against inputs paths
if len(len_pths) == 1:
path_len = 0
for pl in len_pths:
path_len = pl
break
if path_len > 2:
validate_inp_pths = True
dis.fullscreen("Validating...", line2="Outputs")
for idx, txo in self.output_iter():
dis.progress_sofar(idx, self.num_outputs)
if self.session:
if idx == 0:
self.session.update(ser_compact_size(self.num_outputs))
self.session.update(txo.serialize())
output = self.outputs[idx]
parsed_subpaths = output.parse_subpaths(self.my_xfp, self, cosign_xfp)
# perform output validation
af = output.determine_my_change(idx, txo, parsed_subpaths, self)
assert txo.nValue >= 0, "negative output value: o%d" % idx
total_out += txo.nValue
if (txo.nValue == 0) and (af != OP_RETURN):
# OP_RETURN outputs have nValue=0 standard
zero_val_outs += 1
if output.is_change:
self.num_change_outputs += 1
total_change += txo.nValue
if validate_inp_pths:
# Enforce some policy on change outputs:
# - need to "look like" they are going to same wallet as inputs came from
# - range limit last two path components (numerically)
# - same pattern of hard/not hardened components
# - MAX_PATH_DEPTH already enforced before this point
# - (single-sig only) check ther is only 0,1 at change index
is_cmplx = (len(parsed_subpaths) > 1)
for i, xpath in enumerate(parsed_subpaths.values()):
if i not in output.sp_idxs: continue
p = xpath[2:] if output.taproot_subpaths else xpath[1:]
iss = None
if len(p) != path_len:
iss = "has wrong path length (%d not %d)" % (len(p), path_len)
elif tuple(bool(i & 0x80000000) for i in p) not in hard_p:
iss = "has different hardening pattern"
elif tuple(p[:-2]) not in prefix_pths:
iss = "goes to diff path prefix"
elif not is_cmplx and ((p[-2] & 0x7fffffff) not in {0,1}):
iss = "2nd last component not 0 or 1"
elif (p[-1] & 0x7fffffff) > max_gap:
iss = "last component beyond reasonable gap"
if iss:
msg = "Output#%d: %s: %s" % (idx, iss, keypath_to_str(p, skip=0))
if len(hard_p) == 1 and len(prefix_pths) == 1:
# message can be more verbose
# fastest way to get first element from the set
# without modifying the set is for-loop
for hp in hard_p:
break
for pp in prefix_pths:
break
msg += " not %s/{0~1}%s/{0~%d}%s expected" % (
keypath_to_str(pp, skip=0),
"'" if hp[-2] else "",
max_gap,
"'" if hp[-1] else ""
)
self.warnings.append(('Troublesome Change Outs', msg))
if af == OP_RETURN:
num_op_return += 1
if len(txo.scriptPubKey) > 83:
num_op_return_size += 1
elif af is None:
num_unknown_scripts += 1
if self.total_value_out is None:
self.total_value_out = total_out
else:
assert self.total_value_out == total_out, \
'%s != %s' % (self.total_value_out, total_out)
if self.total_change_value is None:
self.total_change_value = total_change
else:
assert self.total_change_value == total_change, \
'%s != %s' % (self.total_change_value, total_change)
# check fee is reasonable
the_fee = self.calculate_fee()
if self.por322:
# Proof of Reserves - nothing more to check - txn is invalid anyways
return
if the_fee is None:
return
if the_fee < 0:
raise FatalPSBTIssue("Outputs worth more than inputs!")
if self.total_value_out:
per_fee = the_fee * 100 / self.total_value_out
else:
per_fee = 100
fee_limit = settings.get('fee_limit', DEFAULT_MAX_FEE_PERCENTAGE)
if fee_limit != -1 and per_fee >= fee_limit:
raise FatalPSBTIssue("Network fee bigger than %d%% of total amount (it is %.0f%%)."
% (fee_limit, per_fee))
if per_fee >= 5:
self.warnings.append(('Big Fee', 'Network fee is more than '
'5%% of total value (%.1f%%).' % per_fee))
if (num_op_return > 1) or num_op_return_size:
mm = ""
if num_op_return > 1:
mm += "\nMultiple OP_RETURN outputs: %d" % num_op_return
if num_op_return_size:
mm += "\nOP_RETURN > 80 bytes"
self.warnings.append(
("OP_RETURN",
"TX may not be relayed by some nodes.%s" % mm))
if num_unknown_scripts:
self.warnings.append(
('Output?',
'Sending to %d not well understood script(s).' % num_unknown_scripts)
)
if zero_val_outs:
self.warnings.append(
('Zero Value',
'Non-standard zero value output(s).')
)
self.consolidation_tx = (self.num_change_outputs == self.num_outputs)
dis.progress_bar_show(1)
if DEBUG:
print("PSBT change outputs: %d out of %d" % (
self.num_change_outputs, len(self.outputs)
))
def consider_inputs(self, cosign_xfp=None):
# Look at the UTXO's that we are spending. Do we have them? Do the
# hashes match, and what values are we getting?
# Important: parse incoming UTXO to build total input value
# check nSequences & nLockTime and warn about TX level locktimes
from glob import dis
foreign = []
total_in = 0
presigned_inputs = set()
# time based relative locks
tb_rel_locks = []
# block height based relative locks
bb_rel_locks = []
smallest_nsequence = 0xffffffff
# collect some input path data from subapths
# later used for change outputs path validation
length_p = set()
hard_pattern = set()
prefix_p = set()
idx_max = 0
my_cnt = 0
prevouts = set()
from_wif_store = []
dis.fullscreen("Validating...", line2="Inputs")
for i, txi in self.input_iter():
dis.progress_sofar(i, self.num_inputs)
# check for duplicate inputs
k = (txi.prevout.hash, txi.prevout.n)
if k in prevouts:
raise FatalPSBTIssue("Duplicate inputs")
if len(prevouts) < 100:
prevouts.add(k)
if self.session:
if i == 0:
self.session.update(ser_compact_size(self.num_inputs))
self.session.update(txi.serialize())
inp = self.inputs[i]
if inp.part_sigs:
# How complete is the set of signatures so far?
# - assuming PSBT creator doesn't give us extra data not required
# - seems harmless if they fool us into thinking already signed; we do nothing
# - could also look at pubkey needed vs. sig provided
# - could consider structure of MofN in p2sh cases
if len(inp.part_sigs) >= len(inp.subpaths):
inp.fully_signed = True
if inp.taproot_key_sig:
inp.fully_signed = True
if inp.utxo:
# Important: they might be trying to trick us with an un-related
# funding transaction (UTXO) that does not match the input signature we're making
# (but if it's segwit, the ploy wouldn't work, Segwit FtW)
# - challenge: it's a straight dsha256() for old serializations, but not for newer
# segwit txn's... plus I don't want to deserialize it here.
try:
observed = uint256_from_str(calc_txid(self.fd, inp.utxo))
except:
raise AssertionError("Trouble parsing UTXO given for input #%d" % i)
assert txi.prevout.hash == observed, "utxo hash mismatch for input #%d" % i
if self.txn_version >= 2:
has_rtl = inp.has_relative_timelock(txi)
if has_rtl:
if has_rtl[0]:
tb_rel_locks.append((i, has_rtl[1]))
else:
bb_rel_locks.append((i, has_rtl[1]))
if txi.nSequence < smallest_nsequence:
smallest_nsequence = txi.nSequence
parsed_subpaths = inp.parse_subpaths(self.my_xfp, self, cosign_xfp)
if not inp.has_utxo():
if inp.sp_idxs and not inp.fully_signed:
# we cannot proceed if the input is ours and there is no UTXO
raise FatalPSBTIssue('Missing own UTXO(s). Cannot determine value being signed')
# input clearly not ours
foreign.append(i)
continue
# pull out just the CTXOut object
# very expensive for non-witness utxo (whole tx)
# less expensive for witness UTXO (just necessary TxOut)
#
utxo = inp.get_utxo(txi.prevout.n)
inp.amount = utxo.nValue
assert inp.amount >= 0, "negative input value: i%d" % i
total_in += inp.amount
inp.af, addr_or_pubkey = utxo.get_address()
# save scriptPubKey of utxo for later use
# needed for P2WPKH scriptCode calculation
# needed for P2PK & P2PKH scriptSig (when finalizing)
# needed for each input if we sign at least one P2TR input
inp.utxo_spk = utxo.scriptPubKey
if inp.sighash == SIGHASH_DEFAULT:
assert inp.af == AF_P2TR, "SIGHASH_DEFAULT outside taproot context"
if inp.sp_idxs:
my_cnt += 1
if inp.fully_signed:
presigned_inputs.add(i)
if inp.sp_idxs and (not inp.fully_signed):
# Look at what kind of input this will be, and therefore what
# type of signing will be required, and which key we need.
# - also validates redeem_script when present
# - also finds appropriate miniscript wallet to be used
inp.determine_my_signing_key(i, addr_or_pubkey, self.my_xfp, self,
parsed_subpaths, utxo)
# determine_my_signing_key may have removed sp_idxs
# meaning we're not going to sign this input - other wallet in use
if not inp.sp_idxs:
continue
# parsed subpaths are OrderedDict - matches sp_idxs
in_wif_store = False
for ii, (key, xpath) in enumerate(parsed_subpaths.items()):
if ii not in inp.sp_idxs: continue
p = xpath[2:] if inp.taproot_subpaths else xpath[1:]
length_p.add(len(p)) # ignore xfp
hard_pattern.add(tuple(bool(i & 0x80000000) for i in p))
prefix_p.add(tuple(p[:-2]))
index = p[-1] & 0x7fffffff
if index > idx_max:
idx_max = index
if self.key_in_wif_store(key):
in_wif_store = True
if in_wif_store:
from_wif_store.append(i)
# iff to UTXO is segwit, then check it's value, and also
# capture that value, since it's supposed to be immutable
# Proof of Reserves PSBT must not modify history
if inp.af and inp.is_segwit and not self.por322:
history.verify_amount(txi.prevout, inp.amount, i)
if inp.af == AF_P2TR:
# based on this we know whether we can drop inp.utxo_spk
# attribute after creating sighash
self.my_tr_in = True
if self.por322 and (i == 0):
# Proof of Reserves 'to_spend' validation
try:
assert inp.utxo, "utxo"
fd = self.fd
old_pos = fd.tell()
fd.seek(inp.utxo[0])
txn_version, marker, flags = unpack("<iBB", fd.read(6))
assert txn_version == 0, TX_VER_ERR
wit_format = (marker == 0 and flags != 0x0)
if not wit_format:
fd.seek(-2, 1)
num_in = deser_compact_size(fd)
assert num_in == 1, "num ins"
tx_inp = CTxIn()
tx_inp.deserialize(fd)
try:
assert len(tx_inp.scriptSig) == 34
assert tx_inp.scriptSig[0] == 0
assert tx_inp.scriptSig[1] == 32
except:
assert False, "scriptSig"
self.por322_msg_hash = tx_inp.scriptSig[2:]
try:
assert tx_inp.prevout.hash == 0
assert tx_inp.prevout.n == 0xffffffff
except:
assert False, "prevout"
num_out = deser_compact_size(fd)
assert num_out == 1, "num outs"
tx_out = CTxOut()
tx_out.deserialize(fd)
self.por322_msg_challenge = tx_out.scriptPubKey
assert tx_out.nValue == 0, "nVal"
fd.seek(old_pos)
except Exception as e:
raise FatalPSBTIssue("i0: invalid BIP-322 'to_spend': %s" % e)
del utxo
if not my_cnt:
raise FatalPSBTIssue('None of the keys involved in this transaction '
'belong to this Coldcard (need %s).' % xfp2str(self.my_xfp))
if not foreign:
# no foreign inputs, we can calculate the total input value
self.total_value_in = total_in
assert total_in > 0 or self.por322, "zero value txn"
else:
# 1+ inputs don't belong to us, we can't calculate the total input value
# OK for multi-party transactions (coinjoin etc.)
assert not self.por322 # cannot have foreign inputs in POR txn
self.total_value_in = None
self.warnings.append(
("Unable to calculate fee", "Some input(s) haven't provided UTXO(s): " + seq_to_str(foreign))
)
if len(presigned_inputs) == self.num_inputs:
# Maybe wrong f cases? Maybe they want to add their
# own signature, even tho N of M is satisfied?!
raise FatalPSBTIssue('Transaction looks completely signed already?')
# We should know pubkey required for each input now.
# - but we may not be the signer for those inputs, which is fine.
# - TODO: but what if not SIGHASH_ALL
no_keys = set(
n
for n,inp in enumerate(self.inputs)
if (not inp.sp_idxs) and (not inp.fully_signed)
)
# HWI blocker
# if len(no_keys) == self.num_inputs:
# # nothing to sign for us
# raise FatalPSBTIssue("Nothing to sign here")
if no_keys:
# This is seen when you re-sign same signed file by accident (multisig)
# - case of len(no_keys)==num_inputs is handled by consider_inputs
self.warnings.append(('Limited Signing',
"We are not signing these inputs, because we either don't know the key,"
" inputs belong to different wallet, or we have already signed: " + seq_to_str(no_keys)))
if presigned_inputs:
# this isn't really even an issue for some complex usage cases
self.warnings.append(('Partly Signed Already',
'Some input(s) provided were already completely signed by other parties: ' +
seq_to_str(presigned_inputs)))
if from_wif_store:
self.warnings.append(("WIF Store", "Some input(s) use key from the WIF store: " +
seq_to_str(from_wif_store)))
if isinstance(self.lock_time, int) and self.lock_time > 0:
if smallest_nsequence == 0xffffffff:
self.warnings.append((
"Bad Locktime",
"Locktime has no effect! None of the nSequences decremented."
))
else:
msg = "This tx can only be spent after "
if self.lock_time < NLOCK_IS_TIME:
msg += "block height of %d" % self.lock_time
else:
try:
dt = datetime_from_timestamp(self.lock_time)
msg += datetime_to_str(dt)
except:
msg += "%d (unix timestamp)" % self.lock_time
msg += " (MTP)" # median time past
msg += "\n"
self.ux_notes.append(("Abs Locktime", msg))
# create UX for users about tx level relative timelocks (nSequence)
self.ux_relative_timelocks(tb_rel_locks, bb_rel_locks)
if MiniScriptWallet.disable_checks:
self.warnings.append(('Danger', 'Some miniscript checks are disabled.'))
if DEBUG:
print("PSBT inputs: %d inputs contain our key, %d fully-signed" % (
my_cnt, len(presigned_inputs)))
dis.progress_bar_show(1)
# useful info from all our parsed paths - will be validated against change outputs
return length_p, hard_pattern, prefix_p, idx_max
def consider_dangerous_sighash(self):
# Check sighash flags are legal, useful, and safe. Warn about
# some risks if user has enabled special sighash values.
# can only be run after consider_outputs is done
sh_unusual = False
none_sh = False
for inp in self.inputs:
if inp.sp_idxs and not inp.fully_signed:
if inp.sighash:
if inp.sighash is not None:
if inp.sighash not in (SIGHASH_ALL, SIGHASH_DEFAULT):
sh_unusual = True
if inp.sighash in (SIGHASH_NONE, SIGHASH_NONE | SIGHASH_ANYONECANPAY):
none_sh = True
if sh_unusual and not settings.get("sighshchk"):
if self.consolidation_tx:
# policy: all inputs must be sighash ALL in purely consolidation txn
raise FatalPSBTIssue("Only sighash ALL/DEFAULT is allowed"
" for pure consolidation transactions.")
if none_sh:
# sighash NONE or NONE|ANYONECANPAY is proposed: block
raise FatalPSBTIssue("Sighash NONE is not allowed as funds could be going anywhere.")
if none_sh:
self.warnings.append(
("Danger", "Destination address can be changed after signing (sighash NONE).")
)
elif sh_unusual:
self.warnings.append(
("Caution", "Some inputs have unusual SIGHASH values not used in typical cases.")
)
def calculate_fee(self):
# what miner's reward is included in txn?
if self.total_value_in is None:
return None
return self.total_value_in - self.total_value_out
@classmethod
def read_psbt(cls, fd):
# read in a PSBT file. Captures fd and keeps it open.
hdr = fd.read(5)
if hdr != b'psbt\xff':
raise ValueError("bad hdr")
rv = cls()
# read main body (globals)
rv.parse(fd)
if rv.txn:
# learn about the bitcoin transaction we are signing.
rv.parse_txn()
assert rv.num_inputs is not None
assert rv.num_outputs is not None
has_musig_inputs = False
rv.inputs = []
for idx in range(rv.num_inputs):
inp = psbtInputProxy(fd, idx)
if inp.is_musig:
has_musig_inputs = True
rv.inputs.append(inp)
rv.outputs = [psbtOutputProxy(fd, idx) for idx in range(rv.num_outputs)]
if has_musig_inputs:
# we need session
rv.session = sha256()
rv.session.update(pack('<i', rv.txn_version))
return rv
def serialize(self, out_fd, upgrade_txn=False):
# Ouput into a file.
wr = lambda *a: self.write(out_fd, *a)
out_fd.write(b'psbt\xff')
if upgrade_txn and self.is_complete():
# write out the ready-to-transmit txn
# - means we are also a PSBT combiner in this case
# - hard tho, due to variable length data.
# - probably a bad idea, so disabled for now
out_fd.write(b'\x01\x00') # keylength=1, key=b'', PSBT_GLOBAL_UNSIGNED_TX
with SizerFile() as fd:
self.finalize(fd)
txn_len = fd.tell()
out_fd.write(ser_compact_size(txn_len))
self.finalize(out_fd)
else:
if not self.is_v2: # can be 0 or None
# provide original txn (unchanged)
wr(PSBT_GLOBAL_UNSIGNED_TX, self.txn)
if self.is_v2:
wr(PSBT_GLOBAL_TX_VERSION, pack('<i', self.txn_version))
if self.fallback_locktime is not None:
wr(PSBT_GLOBAL_FALLBACK_LOCKTIME, pack('<I', self.fallback_locktime))
wr(PSBT_GLOBAL_INPUT_COUNT, ser_compact_size(self.num_inputs))
wr(PSBT_GLOBAL_OUTPUT_COUNT, ser_compact_size(self.num_outputs))
if self.txn_modifiable is not None:
wr(PSBT_GLOBAL_TX_MODIFIABLE, bytes([self.txn_modifiable]))
wr(PSBT_GLOBAL_VERSION, pack('<I', self.version))
if self.xpubs:
for k, v in self.xpubs:
wr(PSBT_GLOBAL_XPUB, v, k)
if self.unknown:
for k, v in self.unknown:
wr(None, v, k)
# sep between globals and inputs
out_fd.write(b'\0')
for idx, inp in enumerate(self.inputs):
inp.serialize(out_fd, self.is_v2)
out_fd.write(b'\0')
for idx, outp in enumerate(self.outputs):
outp.serialize(out_fd, self.is_v2)
out_fd.write(b'\0')
@staticmethod
def check_pubkey_at_path(sv, subpath, target_pk, is_xonly=False):
# derive actual pubkey from private
skp = keypath_to_str(subpath)
node = sv.derive_path(skp)
# check the pubkey of this BIP-32 node
our_pk = node.pubkey()
if is_xonly:
our_pk = our_pk[1:]
if target_pk == our_pk:
return node
return None
@staticmethod
def ecdsa_grind_sign(sk, digest, sighash):
# Do the ACTUAL signature ... finally!!!
# We need to grind sometimes to get a positive R
# value that will encode (after DER) into a shorter string.
# - saves on miner's fee (which might be expected/required)
# - blends in with Bitcoin Core signatures which do this from 0.17.0
n = 0 # retry num
while True:
# time to produce signature on stm32: ~25.1ms
result = ngu.secp256k1.sign(sk, digest, n).to_bytes()
if result[1] < 0x80:
# - no need to check for low S value as those are generated by default
# by secp256k1 lib
# - to produce 71 bytes long signature (both low S low R values),
# we need on average 2 retries
# - worst case ~25 grinding iterations need to be performed total
break
n += 1
# DER serialization after we have low S and low R values in our signature
r = result[1:33]
s = result[33:65]
der_sig = ser_sig_der(r, s, sighash)
return der_sig
@staticmethod
def musig_derive_keyagg_cache(to_derive, agg_key, keyagg_cache):
ck = MUSIG_CHAIN_CODE
agg = agg_key
for idx in to_derive:
I = ngu.hmac.hmac_sha512(ck, agg + pack(">I", idx))
IL, ck = I[:32], I[32:]
ngu.secp256k1.musig_pubkey_ec_tweak_add(keyagg_cache, IL)
agg = keyagg_cache.agg_pubkey().to_bytes()
return agg
def musig_process_input(self, session, inp_idx, inp, keypair, agg_k, der_agg_k,
digest, leaf_hash=b""):
assert session # needed
session_digest, session_rand, round1 = session
my_participant_key = keypair.pubkey().to_bytes()
musig_pubkeys = inp.get_musig_pubkeys()
cosigners = musig_pubkeys.get(agg_k, None)
if (cosigners is None) or (my_participant_key not in cosigners):
return
musig_partial_sigs = inp.get_musig_part_sigs()
musig_pubnonces = inp.get_musig_pubnonces()
keyagg_cache = ngu.secp256k1.MusigKeyAggCache()
# below will sort, but should be already sorted in PSBT
ngu.secp256k1.musig_pubkey_agg(
[ngu.secp256k1.pubkey(pk) for pk in cosigners],
keyagg_cache
)
# verify aggregate key is correct
assert keyagg_cache.agg_pubkey().to_bytes() == agg_k
musig_index = None # index of musig expression in key list
for i, k in enumerate(self.active_miniscript.to_descriptor().keys):
if not isinstance(k, MusigKey):
continue
if k.node.pubkey() == agg_k:
musig_index = i
break
assert musig_index is not None # important, must be there
# get derivation we need to use for musig
sp = inp.get_tr_der_coords_by_key(der_agg_k)
assert sp
to_derive = self.parse_xfp_path(sp)[1:]
# is derived aggregate key xonly ?
dak_xo = int(len(der_agg_k) == 32)
# key is derived inside the key_agg cache
assert self.musig_derive_keyagg_cache(to_derive, agg_k, keyagg_cache)[dak_xo:] == der_agg_k
if not leaf_hash:
# now finally get the output key - only for musig in taproot internal key
tweak_data = der_agg_k
if inp.taproot_merkle_root:
tweak_data += self.get(inp.taproot_merkle_root)
tweak32 = ngu.hash.sha256t(TAP_TWEAK_H, tweak_data, True)
output_key = ngu.secp256k1.musig_pubkey_xonly_tweak_add(keyagg_cache, tweak32)
# tweaked derived aggregate key
der_agg_k = output_key.to_bytes()
my_musig_pubnonces_key = (my_participant_key, der_agg_k, leaf_hash)
inp.musig_added_pubnonces = inp.musig_added_pubnonces or {}
if my_musig_pubnonces_key in musig_partial_sigs:
# we have already signed
return
if my_musig_pubnonces_key in musig_pubnonces:
# I have already provided pubnonce & now I need to use the same secrand
# so that my pubnonce & secnonce match what I have provided in first round
if round1:
raise FatalPSBTIssue("musig needs restart")
else:
if not round1:
raise FatalPSBTIssue("resign")
# sec_rand is pseudo random, derived from session true randomness
sec_rand = ngu.hash.sha256s(session_rand + pack("<I", inp_idx) + pack("<I", musig_index))
# generate musig2 secnonce & pubnonce
sn, pn = ngu.secp256k1.musig_nonce_gen(keypair.pubkey(), sec_rand, keypair.privkey(), digest)
if my_musig_pubnonces_key not in musig_pubnonces:
# I haven't added my pubnoce yet - adding now
my_pn_bytes = pn.to_bytes()
inp.musig_added_pubnonces[my_musig_pubnonces_key] = my_pn_bytes
# we added nonce - done
# strict 1st & 2nd round separation
self.allow_cache_store = True
return
pubnonces = set()
for (pk, ak, lh), pnonce in musig_pubnonces.items():
if (ak == der_agg_k) and (lh == leaf_hash):
# this is the nonce belonging to our aggregate key
pubnonces.add(pnonce)
if pk == my_participant_key:
# required, because if pubnonce is different from what was generated in 1st
# round - signatures will be invalid
assert pnonce == pn.to_bytes()
if len(pubnonces) < len(cosigners):
# cannot sign as number of pubnonces is insufficient
return
# all pubnonces are known - we can sign
aggnonce = ngu.secp256k1.musig_nonce_agg([ngu.secp256k1.MusigPubNonce(pn) for pn in pubnonces])
session = ngu.secp256k1.musig_nonce_process(aggnonce, digest, keyagg_cache)
part_sig = ngu.secp256k1.musig_partial_sign(sn, keypair, keyagg_cache, session)
my_part_sig_bytes = part_sig.to_bytes()
self.sig_added = True
# good for debug - verification of partial musig signature CC created
# assert part_sig.verify(pn, keypair.pubkey(), keyagg_cache, session)
musig_part_sigs = set()
musig_part_sigs.add(my_part_sig_bytes)
inp.musig_added_sigs = inp.musig_added_sigs or {}
# musig pubnonce and part signatures have same key structure
inp.musig_added_sigs[my_musig_pubnonces_key] = my_part_sig_bytes
# our signature added
# session rand no longer needed - as adding signature, terminates 2nd round
# even if we are the first signed input - remove from cache
# other inputs still have access to session_rand from sign_it scope
self.allow_cache_store = False
for (pk, ak, lh), sig in musig_partial_sigs.items():
if (ak == der_agg_k) and (lh == leaf_hash):
# good for debug - verify validity of cosigner musig partial signatures
# other_pn = ngu.secp256k1.MusigPubNonce(musig_pubnonces[(pk,ak,lh)])
# psig = ngu.secp256k1.MusigPartSig(sig)
# assert psig.verify(other_pn, ngu.secp256k1.pubkey(pk), keyagg_cache, session)
musig_part_sigs.add(sig)
if len(musig_part_sigs) < len(cosigners):
# no way to aggregate - threshold not met
return
# we are done and can provide final aggregate signature
agg_sig = ngu.secp256k1.musig_partial_sig_agg(
[ngu.secp256k1.MusigPartSig(sig) for sig in musig_part_sigs],
session
)
assert len(agg_sig) == 64
# return aggregate signature and public key against which it verifies
return agg_sig, der_agg_k
def sign_it(self, alternate_secret=None, my_xfp=None):
# txn is approved. sign all inputs we can sign. add signatures
# - hash the txn first
# - sign all inputs we have the key for
# - inputs might be p2sh, p2pkh and/or segwit style
# - save partial inputs somewhere (append?)
# - update our state with new partial sigs
from glob import dis
from ownership import OWNERSHIP
if my_xfp is None:
my_xfp = self.my_xfp
musig_session = None
musig_round1 = False
if self.session:
# initialize MuSig2 session
session_digest = self.session.digest() + pack('<I', my_xfp) # to differentiate tmp keys
# if we already have it stored, this is 2nd round
# remove it - only one chance to make it right, as consequences for re-use are catastrophic
session_rand = MUSIG_SESSION_CACHE.pop(session_digest, None)
if session_rand is None:
musig_round1 = True
# first round - create new session rand and (maybe) store it for 2nd round
session_rand = ngu.random.bytes(32)
# initialized Musig2 session tuple
musig_session = (session_digest, session_rand, musig_round1)
with stash.SensitiveValues(secret=alternate_secret) as sv:
# Double-check the change outputs are right. This is slow, but critical because
# it detects bad actors, not bugs or mistakes.
# - equivalent check already done for p2sh outputs when we re-built the redeem script
change_outs = [n for n,o in enumerate(self.outputs) if o.is_change]
if change_outs:
dis.fullscreen('Change Check...')
for count, out_idx in enumerate(change_outs):
# only expecting single case, but be general
dis.progress_sofar(count, len(change_outs))
oup = self.outputs[out_idx]
good = 0
for i in oup.sp_idxs:
# for multisig, will be N paths, and exactly one will
# be our key. For single-signer, should always be my XFP
# derive actual pubkey from private
if oup.taproot_subpaths:
pubk = oup.taproot_subpaths[i][0]
sp = oup.taproot_subpaths[i][1][2]
ss = len(oup.taproot_subpaths) == 1
else:
pubk = oup.subpaths[i][0]
sp = oup.subpaths[i][1]
ss = len(oup.subpaths) == 1
# xfp can be zero - substitute with self.my_xfp (not my_xfp as it can be CCC)
sp = self.handle_zero_xfp(self.parse_xfp_path(sp), self.my_xfp, None)
if sp[0] != my_xfp:
# this can happen with CCC, where we have sp_idxs set for both
# CCC key and main xfp
continue
if self.check_pubkey_at_path(sv, sp, self.get(pubk),
is_xonly=bool(oup.taproot_subpaths)):
good += 1
if ss:
OWNERSHIP.note_subpath_used(sp)
if not good:
raise FraudulentChangeOutput(out_idx,
"Deception regarding change output. "
"BIP-32 path doesn't match actual address.")
# progress
dis.fullscreen('Signing...')
# randomize secp context before each signing session
ngu.secp256k1.ctx_rnd()
# Sign individual inputs
for in_idx, txi in self.input_iter():
dis.progress_sofar(in_idx, self.num_inputs)
inp = self.inputs[in_idx]
if not inp.has_utxo():
# maybe they didn't provide the UTXO
continue
if not inp.sp_idxs:
# we don't know the key for this input
continue
if inp.fully_signed:
# for multisig, it's possible I need to add another sig
# but in other cases, no more signatures are possible
continue
inp.handle_none_sighash()
if self.por322:
assert inp.sighash in [SIGHASH_ALL, SIGHASH_DEFAULT], "POR sighash not ALL/DEFAULT"
# decide if it is appropriate to drop sighash from PSBT
if inp.taproot_subpaths:
drop_sighash = (inp.sighash == SIGHASH_DEFAULT)
else:
drop_sighash = (inp.sighash == SIGHASH_ALL)
schnorrsig = False
tr_sh = []
to_sign = []
if inp.is_miniscript:
for i in inp.sp_idxs:
# get node required
if inp.taproot_subpaths:
schnorrsig = True
pubk = inp.taproot_subpaths[i][0]
sp = inp.taproot_subpaths[i][1][2]
else:
pubk = inp.subpaths[i][0]
sp = inp.subpaths[i][1]
which_key = self.get(pubk)
is_xonly = len(which_key) == 32
wif_store_key = self.key_in_wif_store(which_key)
if wif_store_key:
node = node_from_privkey(self.wif_store[wif_store_key])
else:
# xfp can be zero - substitute with self.my_xfp (not my_xfp as it can be CCC)
sp = self.handle_zero_xfp(self.parse_xfp_path(sp), self.my_xfp, None)
if sp[0] != my_xfp:
# this can happen with CCC, where we have sp_idxs set for both
# CCC key and main xfp
continue
# expensive test, but works... and important
node = self.check_pubkey_at_path(sv, sp, which_key, is_xonly=is_xonly)
if not node:
continue
to_sign.append((node, pubk))
if is_xonly and self.active_miniscript.to_descriptor().tapscript:
# get the script
inner_tr_sh = []
assert self.active_miniscript
xfp_paths = [self.handle_zero_xfp(self.parse_xfp_path(x[2]), self.my_xfp, None)
for _, x in inp.taproot_subpaths]
der_d = self.active_miniscript.derive_desc(xfp_paths)
# mapping from script to leaf version
taproot_scripts = inp.get_taproot_scripts()
for leaf in der_d.tapscript.iter_leaves():
# always exact check/match the script, if we would generate such
scr = leaf.compile()
if scr not in taproot_scripts:
continue
for k in leaf.keys:
is_musig = False
if isinstance(k, MusigKey):
agg_k = k.aggregate_pubkey()
der_agg_k = k.node.pubkey()
is_musig = (agg_k.to_bytes(), der_agg_k)
kk = [mk.key_bytes() for mk in k.keys]
else:
kk = [k.key_bytes()]
if which_key in kk:
inner_tr_sh.append((scr, taproot_scripts[scr], is_musig))
tr_sh.append(inner_tr_sh)
del taproot_scripts
else:
# single pubkey <=> single key
assert len(inp.sp_idxs) == 1
sp_idx = inp.sp_idxs[0]
assert not inp.added_sigs, "already done??"
assert not inp.taproot_key_sig, "already done taproot??"
if inp.taproot_subpaths:
schnorrsig = True
pubk = inp.taproot_subpaths[sp_idx][0]
sp = inp.taproot_subpaths[sp_idx][1][2]
else:
pubk = inp.subpaths[sp_idx][0]
sp = inp.subpaths[sp_idx][1]
pk = self.get(pubk)
int_pth = None
wif_store_key = self.key_in_wif_store(pk)
if wif_store_key:
node = node_from_privkey(self.wif_store[wif_store_key])
else:
int_pth = self.handle_zero_xfp(self.parse_xfp_path(sp), self.my_xfp, None)
skp = keypath_to_str(int_pth)
# get node required
node = sv.derive_path(skp, register=False)
# expensive test, but works... and important
pu = node.pubkey()
if schnorrsig:
pu = pu[1:]
assert pu == pk, "Path (%s) led to wrong pubkey for input#%d" % (skp, in_idx)
to_sign.append((node, pubk))
if int_pth:
# track wallet usage
OWNERSHIP.note_subpath_used(int_pth)
# normal operation with valid sighash
digest = None
if not inp.is_segwit:
# Hash by serializing/blanking various subparts of the transaction
txi.scriptSig = inp.get_scriptSig()
digest = self.make_txn_sighash(in_idx, txi, inp.sighash)
else:
# Hash the inputs and such in totally new ways, based on BIP-143
if not inp.taproot_subpaths:
digest = self.make_txn_segwit_sighash(in_idx, txi, inp.amount,
inp.segwit_v0_scriptCode(),
inp.sighash)
# else:
# sighashes for taproot internal key & tapscript spends are calculated later
if digest and sv.deltamode:
# Current user is actually a thug with a slightly wrong PIN, so we
# do have access to the private keys and could sign txn, but we
# are going to silently corrupt our signatures.
digest = ngu.hash.sha256d(digest)
# we no longer need utxo_spk if:
# - none of the inputs that we're signing is P2TR
# - this input is not P2PK or P2PKH, otherwise we need utxo_spk for scriptSig
if not self.my_tr_in and (inp.af not in (AF_BARE_PK, AF_CLASSIC)):
try:
del inp.utxo_spk
except AttributeError: pass # may not have UTXO
# The precious private key we need
for i, (node, pk_coord) in enumerate(to_sign):
sk = node.privkey()
# Do the ACTUAL signature ... finally!!!
if schnorrsig:
kp = ngu.secp256k1.keypair(sk)
xonly_pk = kp.xonly_pubkey().to_bytes()
if inp.taproot_internal_key:
# if internal key is provided in PSBT use that
internal_key = self.get(inp.taproot_internal_key)
elif len(inp.ik_idx) == 1:
# if not - it is in taproot paths
# but there can be multiple - in case of musig
internal_key = self.get(inp.taproot_subpaths[inp.ik_idx[0]][0])
else:
raise ValueError("Internal key missing")
if xonly_pk == internal_key:
# internal key is our key -> easy
# BIP 341 states: "If the spending conditions do not require a script path,
# the output key should commit to an unspendable script path instead of having no script path.
# This can be achieved by computing the output key point as Q = P + int(hashTapTweak(bytes(P)))G."
tweak = xonly_pk
if inp.taproot_merkle_root:
# we have a script path but internal key is spendable by us
# merkle root needs to be added to tweak with internal key
# merkle root was already verified against registered script in determine_my_signing_key
tweak += self.get(inp.taproot_merkle_root)
tweak = ngu.hash.sha256t(TAP_TWEAK_H, tweak, True)
kpt = kp.xonly_tweak_add(tweak)
digest = self.make_txn_taproot_sighash(in_idx, hash_type=inp.sighash)
if sv.deltamode:
digest = ngu.hash.sha256d(digest)
sig = ngu.secp256k1.sign_schnorr(kpt, digest, ngu.random.bytes(32))
if inp.sighash != SIGHASH_DEFAULT:
sig += bytes([inp.sighash])
# in the common case of SIGHASH_DEFAULT, encoded as '0x00', a space optimization MUST be made by
# 'omitting' the sighash byte, resulting in a 64-byte signature with SIGHASH_DEFAULT assumed
inp.taproot_key_sig = sig
self.sig_added = True
# debug
# ngu.secp256k1.verify_schnorr(sig, digest, kpt.xonly_pubkey())
del kpt
elif isinstance(self.active_miniscript.to_descriptor().key, MusigKey):
# internal key is musig
agg_k = self.active_miniscript.to_descriptor().key.node.pubkey()
digest = self.make_txn_taproot_sighash(in_idx, hash_type=inp.sighash)
if sv.deltamode:
digest = ngu.hash.sha256d(digest)
complete = self.musig_process_input(musig_session, in_idx, inp, kp,
agg_k, internal_key, digest)
if complete:
agg_sig, pubkey = complete
# we can finalize musig in taproot internal key
if inp.sighash != SIGHASH_DEFAULT:
agg_sig += bytes([inp.sighash])
inp.taproot_key_sig = agg_sig
# debug
# ngu.secp256k1.verify_schnorr(agg_sig, digest, ngu.secp256k1.xonly_pubkey(pubkey[1:]))
if tr_sh:
# in tapscript keys are not tweaked, just sign with the key in the script
# signing tapscript even if we already signed internal key
taproot_script_sigs = inp.get_taproot_script_sigs()
inp.tr_added_sigs = inp.tr_added_sigs or {}
for taproot_script, leaf_ver, is_musig in tr_sh[i]:
tlh = tapleaf_hash(taproot_script, leaf_ver)
digest = self.make_txn_taproot_sighash(in_idx, hash_type=inp.sighash,
scriptpath=True,
script=taproot_script,
leaf_ver=leaf_ver)
if sv.deltamode:
digest = ngu.hash.sha256d(digest)
if is_musig:
agg_k, der_agg_k = is_musig
assert len(der_agg_k) == 33
_key = (der_agg_k[1:], tlh)
if _key in taproot_script_sigs:
continue # already done ?
complete = self.musig_process_input(musig_session, in_idx, inp, kp,
agg_k, der_agg_k, digest, tlh)
if complete:
agg_sig, pubkey = complete
assert der_agg_k == pubkey
if inp.sighash != SIGHASH_DEFAULT:
agg_sig += bytes([inp.sighash])
# separate container for PSBT_IN_TAP_SCRIPT_SIG that we added
inp.tr_added_sigs[_key] = agg_sig
# debug
# ngu.secp256k1.verify_schnorr(agg_sig, digest, ngu.secp256k1.xonly_pubkey(pubkey[1:]))
else:
_key = (xonly_pk, tlh)
if _key in taproot_script_sigs:
continue # already done ?
sig = ngu.secp256k1.sign_schnorr(sk, digest, ngu.random.bytes(32))
# in the common case of SIGHASH_DEFAULT, encoded as '0x00', a space optimization MUST be made by
# 'omitting' the sighash byte, resulting in a 64-byte signature with SIGHASH_DEFAULT assumed
if inp.sighash != SIGHASH_DEFAULT:
sig += bytes([inp.sighash])
# separate container for PSBT_IN_TAP_SCRIPT_SIG that we added
inp.tr_added_sigs[_key] = sig
self.sig_added = True
# debug
# ngu.secp256k1.verify_schnorr(sig, digest, kp.xonly_pubkey())
del kp
else:
# ECDSA signing
der_sig = self.ecdsa_grind_sign(sk, digest, inp.sighash)
inp.added_sigs = inp.added_sigs or []
inp.added_sigs.append((pk_coord, der_sig))
self.sig_added = True
# private key no longer required
stash.blank_object(sk)
stash.blank_object(node)
del sk, node
if self.is_v2:
self.set_modifiable_flag(inp)
if drop_sighash:
# only drop after modifiable is set, in case of PSBTv2
# SIGHASH_DEFAULT if taproot
# SIGHASH_ALL if non-taproot
inp.sighash = None
del to_sign
gc.collect()
# store musig session - only at the end of this function execution
# if any exceptions were raised - just do not store
if musig_session and musig_round1 and self.allow_cache_store:
MUSIG_SESSION_CACHE[session_digest] = session_rand
# done.
dis.progress_bar_show(1)
def set_modifiable_flag(self, inp):
# only for PSBTv2
# sighash needs to be properly set on psbtInputProxy object before this runs
# TODO possible to also cross-check with sighash from signature:
# 1. witnes/scriptSig in serialized tx in PSBT
# 2. psbt meta fields partial_sigs, taproot_key_sig and taproot_script_sigs
if self.txn_modifiable is None:
# set to inputs/outputs modifiable
# has SINGLE to false
self.txn_modifiable = 3
if not (inp.sighash & SIGHASH_ANYONECANPAY):
# Bit 0 is the Inputs Modifiable flag - set to 0
if self.txn_modifiable & 1:
self.txn_modifiable &= ~1
out_type = inp.sighash & 0x7f # regardless of ANYONECANPAY
if out_type != SIGHASH_NONE:
# Bit 1 is the Outputs Modifiable flag - set to 0
if self.txn_modifiable & 2:
self.txn_modifiable &= ~2
if out_type == SIGHASH_SINGLE:
# Bit 2 is the Has SIGHASH_SINGLE flag - set it to 1
self.txn_modifiable |= 4
def make_txn_sighash(self, replace_idx, replacement, sighash_type):
# calculate the hash value for one input of current transaction
# - blank all script inputs
# - except one single tx in, which is provided
# - serialize that without witness data
# - sha256 over that
fd = self.fd
old_pos = fd.tell()
# sighash regardless of ANYONECANPAY input part
out_sighash_type = sighash_type & 0x7f
rv = sha256()
# version number
rv.update(pack('<i', self.txn_version)) # nVersion
# inputs
num_inputs = 1 if sighash_type & SIGHASH_ANYONECANPAY else self.num_inputs
rv.update(ser_compact_size(num_inputs))
for in_idx, txi in self.input_iter():
if in_idx == replace_idx:
assert not self.inputs[in_idx].is_segwit
assert replacement.scriptSig
rv.update(replacement.serialize())
elif not (sighash_type & SIGHASH_ANYONECANPAY):
if out_sighash_type in (SIGHASH_NONE, SIGHASH_SINGLE):
# do not include sequence of other inputs (zero them for digest)
# which means that they can be replaced
txi.nSequence = 0
txi.scriptSig = b''
rv.update(txi.serialize())
# else:
# is SIGHASH_ANYONECANPAY so we do not include any other inputs
# outputs
if out_sighash_type == SIGHASH_NONE:
rv.update(ser_compact_size(0))
elif out_sighash_type == SIGHASH_SINGLE:
rv.update(ser_compact_size(replace_idx+1))
assert replace_idx < self.num_outputs, "SINGLE corresponding output (%d) missing" % replace_idx
for out_idx, txo in self.output_iter():
if out_idx < replace_idx:
rv.update(CTxOut(-1).serialize())
if out_idx == replace_idx:
rv.update(txo.serialize())
else:
assert out_sighash_type == SIGHASH_ALL
rv.update(ser_compact_size(self.num_outputs))
for out_idx, txo in self.output_iter():
rv.update(txo.serialize())
# locktime, sighash_type
rv.update(pack('<II', self.lock_time, sighash_type))
fd.seek(old_pos)
# double SHA256
return ngu.hash.sha256s(rv.digest())
def make_txn_taproot_sighash(self, input_index, hash_type=SIGHASH_DEFAULT, scriptpath=False, script=None,
codeseparator_pos=-1, annex=None, leaf_ver=TAPROOT_LEAF_TAPSCRIPT):
# BIP-341
fd = self.fd
old_pos = fd.tell()
out_type = SIGHASH_ALL if (hash_type == SIGHASH_DEFAULT) else (hash_type & 3)
in_type = hash_type & SIGHASH_ANYONECANPAY
if not self.hashValues and in_type != SIGHASH_ANYONECANPAY:
hashPrevouts = sha256()
hashSequence = sha256()
hashValues = sha256()
hashScriptPubKeys = sha256()
# input side
for in_idx, txi in self.input_iter():
hashPrevouts.update(txi.prevout.serialize())
hashSequence.update(pack("<I", txi.nSequence))
inp = self.inputs[in_idx]
hashValues.update(pack("<q", inp.amount))
hashScriptPubKeys.update(ser_string(inp.utxo_spk))
self.hashPrevouts = hashPrevouts.digest()
self.hashSequence = hashSequence.digest()
self.hashValues = hashValues.digest()
self.hashScriptPubKeys = hashScriptPubKeys.digest()
del hashPrevouts, hashSequence, hashValues, hashScriptPubKeys, txi
gc.collect()
if not self.hashOutputs and out_type == SIGHASH_ALL:
# output side
hashOutputs = sha256()
for out_idx, txo in self.output_iter():
hashOutputs.update(txo.serialize())
self.hashOutputs = hashOutputs.digest()
del hashOutputs, txo
gc.collect()
msg = bytes([0, hash_type])
msg += pack('<i', self.txn_version)
msg += pack('<I', self.lock_time)
if in_type != SIGHASH_ANYONECANPAY:
# sha_prevouts
msg += self.hashPrevouts
# sha_amounts
msg += self.hashValues
# sha_scriptpubkeys
msg += self.hashScriptPubKeys
# sha_sequences
msg += self.hashSequence
if out_type == SIGHASH_ALL:
# sha_outputs
msg += self.hashOutputs
# spend type
spend_type = 0
if annex is not None:
spend_type |= 1
if scriptpath:
spend_type |= 2
msg += bytes([spend_type])
if in_type == SIGHASH_ANYONECANPAY:
for in_idx, txi in self.input_iter():
if input_index == in_idx:
inp = self.inputs[in_idx]
msg += txi.prevout.serialize()
msg += pack("<q", inp.amount)
msg += ser_string(inp.utxo_spk)
msg += pack("<I", txi.nSequence)
break
else:
assert False, "ANYONECANPAY inpupt idx"
else:
msg += pack('<I', input_index)
if (spend_type & 1):
msg += ngu.hash.sha256s(ser_string(annex))
if out_type == SIGHASH_SINGLE:
assert input_index < self.num_outputs, "SINGLE corresponding output (%d) missing" % input_index
for out_idx, txo in self.output_iter():
if input_index == out_idx:
msg += ngu.hash.sha256s(txo.serialize())
break
if scriptpath:
msg += tapleaf_hash(script, leaf_ver)
msg += bytes([0])
msg += pack("<i", codeseparator_pos)
assert len(msg) == 175 - (in_type == SIGHASH_ANYONECANPAY) * 49 - (
out_type != SIGHASH_ALL and out_type != SIGHASH_SINGLE) * 32 + (
annex is not None) * 32 + scriptpath * 37, "taproot SigMsg length does not make sense"
fd.seek(old_pos)
sighash = ngu.hash.sha256t(TAP_SIGHASH_H, msg, True)
return sighash
def make_txn_segwit_sighash(self, replace_idx, replacement, amount, scriptCode, sighash_type):
# Implement BIP 143 hashing algo for signature of segwit programs.
# see <https://github.com/bitcoin/bips/blob/master/bip-0143.mediawiki>
#
fd = self.fd
old_pos = fd.tell()
# sighash regardless of ANYONECANPAY input part
out_sighash_type = sighash_type & 0x7f
if self.hashPrevouts and sighash_type == SIGHASH_ALL:
hashPrevouts = self.hashPrevouts
hashSequence = self.hashSequence
hashOutputs = self.hashOutputs
else:
# input side
hashPrevouts = sha256()
hashSequence = sha256()
if not (sighash_type & SIGHASH_ANYONECANPAY):
for in_idx, txi in self.input_iter():
hashPrevouts.update(txi.prevout.serialize())
if out_sighash_type == SIGHASH_ALL:
hashSequence.update(pack("<I", txi.nSequence))
hashPrevouts = ngu.hash.sha256s(hashPrevouts.digest())
if out_sighash_type == SIGHASH_ALL:
hashSequence = ngu.hash.sha256s(hashSequence.digest())
# output side
hashOutputs = sha256()
if out_sighash_type == SIGHASH_ALL:
for out_idx, txo in self.output_iter():
hashOutputs.update(txo.serialize())
hashOutputs = ngu.hash.sha256s(hashOutputs.digest())
elif out_sighash_type == SIGHASH_SINGLE:
# Even though below case is consensus valid, we block it.
# If users do not want to sign any outputs, NONE sighash flag
# should be used instead.
assert replace_idx < self.num_outputs, \
"SINGLE corresponding output (%d) missing" % replace_idx
for out_idx, txo in self.output_iter():
if out_idx == replace_idx:
hashOutputs = ngu.hash.sha256d(txo.serialize())
else:
assert out_sighash_type == SIGHASH_NONE
if sighash_type == SIGHASH_ALL:
# cache this multitude of hashes
self.hashPrevouts = hashPrevouts
self.hashSequence = hashSequence
self.hashOutputs = hashOutputs
gc.collect()
rv = sha256()
# version number
rv.update(pack('<i', self.txn_version)) # nVersion
rv.update(hashPrevouts if isinstance(hashPrevouts, bytes) else bytes(32))
rv.update(hashSequence if isinstance(hashSequence, bytes) else bytes(32))
rv.update(replacement.prevout.serialize())
# the "scriptCode" ... not well understood
assert scriptCode, 'need scriptCode here'
rv.update(scriptCode)
rv.update(pack("<q", amount))
rv.update(pack("<I", replacement.nSequence))
rv.update(hashOutputs if isinstance(hashOutputs, bytes) else bytes(32))
# locktime, sighash_type
rv.update(pack('<II', self.lock_time, sighash_type))
fd.seek(old_pos)
# double SHA256
return ngu.hash.sha256s(rv.digest())
def miniscript_input_complete(self, inp):
desc = self.active_miniscript.to_descriptor()
if desc.is_basic_multisig:
# we can only finalize multisig inputs from all miniscript set
M, N = desc.miniscript.m_n()
ll = 0
if inp.part_sigs:
ll += len(inp.part_sigs)
if inp.added_sigs:
ll += len(inp.added_sigs)
if ll >= M:
return True
return False
def is_complete(self):
# Are all the inputs (now) signed?
# plus we added some signatures
for i, inp in enumerate(self.inputs):
if inp.fully_signed:
# was fully signed before (fully signed works with part_sigs only)
continue
elif inp.taproot_key_sig:
continue
elif inp.is_miniscript and self.active_miniscript:
if self.miniscript_input_complete(inp):
continue
return False
ll = len(inp.added_sigs) if inp.added_sigs else 0
ll += len(inp.part_sigs) if inp.part_sigs else 0
if inp.subpaths and (len(inp.subpaths) == ll):
continue
# input is not signed - and therefore tx is not complete
return False
return True
def multisig_signatures(self, inp):
assert self.active_miniscript
desc = self.active_miniscript.to_descriptor()
assert desc.is_basic_multisig
M, N = desc.miniscript.m_n()
# collect all signatures and parse them if some just coords
full_sigs = {}
if inp.added_sigs:
# what we add is always in memory (not coordinates to PSRAM)
for pk_coord, sig in inp.added_sigs:
full_sigs[self.get(pk_coord)] = sig
if inp.part_sigs:
# what others added is always just coordinates
for k, v in inp.part_sigs:
full_sigs[self.get(k)] = self.get(v)
# ===
if desc.is_sortedmulti:
# BIP-67 easy just sort by public keys
sigs = [sig for pk, sig in sorted(full_sigs.items())]
else:
# need to respect the order of keys in actual descriptor
sigs = []
for key in desc.keys:
for k, v in inp.subpaths:
pk = self.get(k)
xfp = self.handle_zero_xfp(self.parse_xfp_path(v), self.my_xfp, None)[0]
# if xfp matches but pk not in all_sigs -> signer haven't signed
# it is ok in threshold multisig - just skip
if (key.origin.cc_fp == xfp) and (pk in full_sigs):
sigs.append(full_sigs[pk])
break
# save space and only provide necessary amount of signatures (smaller tx, less fees)
return sigs[:M]
def singlesig_signature(self, inp):
# return signature that we added
# or one signature from partial sigs if input is fully sign
if inp.added_sigs:
assert len(inp.added_sigs) == 1
return self.get(inp.added_sigs[0][0]), inp.added_sigs[0][1]
if inp.part_sigs:
assert len(inp.part_sigs) == 1
pk, sig = inp.part_sigs[0]
return self.get(pk), self.get(sig)
def miniscript_xfps_needed(self):
# provide the set of xfp's that still need to sign PSBT
# - used to find which multisig-signer needs to go next
rv = set()
done_keys = set()
ignore_keys = set()
for inp in self.inputs:
if inp.fully_signed:
continue
if inp.taproot_subpaths:
if inp.taproot_key_sig:
# already signed
continue
# only get this once for each input
if inp.taproot_script_sigs:
for xo, _ in inp.get_taproot_script_sigs():
done_keys.add(xo)
if inp.tr_added_sigs:
for (xo, _) in inp.tr_added_sigs:
done_keys.add(xo)
if inp.is_musig:
# in how many musig expressions is this key included
key_musig_num_map = {}
for ak, key_lst in inp.get_musig_pubkeys().items():
# filter out just musig aggregate keys (they are not co-signers)
ignore_keys.add(unpack('<I', hash160(ak)[:4])[0])
for k in key_lst:
if k not in key_musig_num_map:
key_musig_num_map[k] = 1
else:
key_musig_num_map[k] += 1
key_signed_num_map = {}
for pk, *_ in inp.get_musig_part_sigs():
if pk not in key_signed_num_map:
key_signed_num_map[pk] = 1
else:
key_signed_num_map[pk] += 1
if inp.musig_added_sigs:
for pk, *_ in inp.musig_added_sigs:
if pk not in key_signed_num_map:
key_signed_num_map[pk] = 1
else:
key_signed_num_map[pk] += 1
for key, num in key_signed_num_map.items():
xkey = key[1:]
if key_musig_num_map.get(key) == num:
# all musig expressions signed
done_keys.add(xkey)
else:
# not all musig expression signed
# BUT maybe we added to done keys because some signatures were added
done_keys.discard(xkey) # remove
for i, (k, v) in enumerate(inp.taproot_subpaths):
xpk = self.get(k)
if inp.ik_idx == i:
# internal key
if self.active_miniscript.ik_u:
# no way to sign with unspend
continue
else:
if xpk in done_keys:
continue
# add xfp
xfp = self.handle_zero_xfp(self.parse_xfp_path(v[2]), self.my_xfp, None)[0]
if xfp in ignore_keys: continue
rv.add(xfp)
else:
if inp.part_sigs:
for k, _ in inp.part_sigs:
done_keys.add(self.get(k))
if inp.added_sigs:
for k, _ in inp.added_sigs:
done_keys.add(self.get(k))
for k, v in inp.subpaths:
if self.get(k) not in done_keys:
xfp = self.handle_zero_xfp(self.parse_xfp_path(v), self.my_xfp, None)[0]
rv.add(xfp)
return rv, ignore_keys
def finalize(self, fd):
# Stream out the finalized transaction, with signatures applied
# - raise if not complete already
# - returns the TXID of resulting transaction
# - but in segwit case, needs to re-read to calculate it
# - fd must be read/write and seekable to support txid calc
fd.write(pack('<i', self.txn_version)) # nVersion
# does this txn require witness data to be included?
# - yes, if the original txn had some
# - yes, if we did a segwit signature on any input
needs_witness = self.had_witness or any(i.is_segwit for i in self.inputs if i)
if needs_witness:
# zero marker, and flags=0x01
fd.write(b'\x00\x01')
body_start = fd.tell()
# inputs
fd.write(ser_compact_size(self.num_inputs))
for in_idx, txi in self.input_iter():
inp = self.inputs[in_idx]
# first check - if no signature(s) - fail soon
if inp.is_miniscript and not inp.taproot_key_sig:
assert self.miniscript_input_complete(inp), 'Incomplete signature set on input #%d' % in_idx
else:
# single signature
if inp.af == AF_P2TR:
assert inp.taproot_key_sig, 'No signature on input #%d' % in_idx
else:
ssig = self.singlesig_signature(inp)
assert ssig, 'No signature on input #%d' % in_idx
if inp.is_segwit:
# p2sh-p2wsh & p2sh-p2wpkh still need redeem here (redeem is witness scriptPubKey)
txi.scriptSig = inp.get_scriptSig()
# for p2wpkh & p2wsh inp.scriptSig is b'' (no redeem script bloat anymore) - do not ser_string
if txi.scriptSig:
txi.scriptSig = ser_string(inp.get_scriptSig())
# Actual signature will be in witness data area
else:
# insert the new signature(s), assuming fully signed txn.
if inp.is_miniscript:
# p2sh multisig (non-segwit)
sigs = self.multisig_signatures(inp)
ss = b"\x00"
for sig in sigs:
ss += ser_push_data(sig)
ss += ser_push_data(self.get(inp.redeem_script))
txi.scriptSig = ss
else:
pubkey, der_sig = ssig
txi.scriptSig = ser_push_data(der_sig) + ser_push_data(pubkey)
fd.write(txi.serialize())
# outputs
fd.write(ser_compact_size(self.num_outputs))
for out_idx, txo in self.output_iter():
fd.write(txo.serialize())
# capture change output amounts (if segwit)
if self.outputs[out_idx].is_change and self.outputs[out_idx].witness_script:
history.add_segwit_utxos(out_idx, txo.nValue)
body_end = fd.tell()
if needs_witness:
# witness values
# - preserve any given ones, add ours
for in_idx, wit in self.input_witness_iter():
inp = self.inputs[in_idx]
if inp.is_segwit:
# put in new sig: wit is a CTxInWitness
assert not wit.scriptWitness.stack, 'replacing non-empty?'
if inp.taproot_key_sig:
# segwit v1 (taproot)
w = inp.taproot_key_sig
if isinstance(w, tuple):
w = self.get(w)
# can be 65 bytes if sighash != SIGHASH_DEFAULT (0x00)
assert len(w) in (64, 65)
wit.scriptWitness.stack = [w]
elif inp.is_miniscript:
sigs = self.multisig_signatures(inp)
wit.scriptWitness.stack = [b""] + sigs + [self.get(inp.witness_script)]
else:
# segwit v0
pubkey, der_sig = self.singlesig_signature(inp)
assert pubkey[0] in {0x02, 0x03} and len(pubkey) == 33, "bad v0 pubkey"
wit.scriptWitness.stack = [der_sig, pubkey]
fd.write(wit.serialize())
# locktime
fd.write(pack('<I', self.lock_time))
# calc transaction ID
if not needs_witness:
# easy w/o witness data
txid = ngu.hash.sha256s(fd.checksum.digest())
else:
if self.session:
# musig transaction with session already calculated, which is basically TXID
# just needs another single SHA256 + byte reverse done few lines below
txid = ngu.hash.sha256s(self.session.digest())
else:
# legacy cost here for segwit: re-read what we just wrote
txid = calc_txid(fd, (0, fd.tell()), (body_start, body_end-body_start))
history.add_segwit_utxos_finalize(txid)
return B2A(bytes(reversed(txid)))
# EOF