def sign_tx(self, psbt: PSBT) -> Dict[str, str]:
def find_our_key(
keypaths: Dict[bytes, Sequence[int]]
) -> Tuple[Optional[bytes], Optional[Sequence[int]]]:
"""
Keypaths is a map of pubkey to hd keypath, where the first element in the keypath is the master fingerprint. We attempt to find the key which belongs to the BitBox02 by matching the fingerprint, and then matching the pubkey.
Returns the pubkey and the keypath, without the fingerprint.
"""
for pubkey, keypath_with_fingerprint in keypaths.items():
fp, keypath = keypath_with_fingerprint[0], keypath_with_fingerprint[1:]
# Cheap check if the key is ours.
if fp != master_fp:
continue
# Expensive check if the key is ours.
# TODO: check for fingerprint collision
# keypath_account = keypath[:-2]
return pubkey, keypath
return None, None
def get_simple_type(
output: CTxOut, redeem_script: bytes
) -> bitbox02.btc.BTCScriptConfig.SimpleType:
if is_p2pkh(output.scriptPubKey):
raise BadArgumentError(
"The BitBox02 does not support legacy p2pkh scripts"
)
if is_p2wpkh(output.scriptPubKey):
return bitbox02.btc.BTCScriptConfig.P2WPKH
if output.is_p2sh() and is_p2wpkh(redeem_script):
return bitbox02.btc.BTCScriptConfig.P2WPKH_P2SH
raise BadArgumentError(
"Input script type not recognized of input {}.".format(input_index)
)
master_fp = struct.unpack("<I", unhexlify(self.get_master_fingerprint_hex()))[0]
inputs: List[bitbox02.BTCInputType] = []
bip44_account = None
# One pubkey per input. The pubkey identifies the key per input with which we sign. There
# must be exactly one pubkey per input that belongs to the BitBox02.
found_pubkeys: List[bytes] = []
for input_index, (psbt_in, tx_in) in builtins.enumerate(
zip(psbt.inputs, psbt.tx.vin)
):
if psbt_in.sighash and psbt_in.sighash != 1:
raise BadArgumentError(
"The BitBox02 only supports SIGHASH_ALL. Found sighash: {}".format(
psbt_in.sighash
)
)
utxo = None
prevtx = None
# psbt_in.witness_utxo was originally used for segwit utxo's, but since it was
# discovered that the amounts are not correctly committed to in the segwit sighash, the
# full prevtx (non_witness_utxo) is supplied for both segwit and non-segwit inputs.
# See
# - https://medium.com/shiftcrypto/bitbox-app-firmware-update-6-2020-c70f733a5330
# - https://blog.trezor.io/details-of-firmware-updates-for-trezor-one-version-1-9-1-and-trezor-model-t-version-2-3-1-1eba8f60f2dd.
# - https://github.com/zkSNACKs/WalletWasabi/pull/3822
# The BitBox02 for now requires the prevtx, at least until Taproot activates.
if psbt_in.non_witness_utxo:
if tx_in.prevout.hash != psbt_in.non_witness_utxo.sha256:
raise BadArgumentError(
"Input {} has a non_witness_utxo with the wrong hash".format(
input_index
)
)
utxo = psbt_in.non_witness_utxo.vout[tx_in.prevout.n]
prevtx = psbt_in.non_witness_utxo
elif psbt_in.witness_utxo:
utxo = psbt_in.witness_utxo
if utxo is None:
raise BadArgumentError("No utxo found for input {}".format(input_index))
if prevtx is None:
raise BadArgumentError(
"Previous transaction missing for input {}".format(input_index)
)
found_pubkey, keypath = find_our_key(psbt_in.hd_keypaths)
if not found_pubkey:
raise BadArgumentError("No key found for input {}".format(input_index))
assert keypath is not None
found_pubkeys.append(found_pubkey)
# TOOD: validate keypath
if bip44_account is None:
bip44_account = keypath[2]
elif bip44_account != keypath[2]:
raise BadArgumentError(
"The bip44 account index must be the same for all inputs and changes"
)
simple_type = get_simple_type(utxo, psbt_in.redeem_script)
script_config_index_map = {
bitbox02.btc.BTCScriptConfig.P2WPKH: 0,
bitbox02.btc.BTCScriptConfig.P2WPKH_P2SH: 1,
}
inputs.append(
{
"prev_out_hash": ser_uint256(tx_in.prevout.hash),
"prev_out_index": tx_in.prevout.n,
"prev_out_value": utxo.nValue,
"sequence": tx_in.nSequence,
"keypath": keypath,
"script_config_index": script_config_index_map[simple_type],
"prev_tx": {
"version": prevtx.nVersion,
"locktime": prevtx.nLockTime,
"inputs": [
{
"prev_out_hash": ser_uint256(prev_in.prevout.hash),
"prev_out_index": prev_in.prevout.n,
"signature_script": prev_in.scriptSig,
"sequence": prev_in.nSequence,
}
for prev_in in prevtx.vin
],
"outputs": [
{
"value": prev_out.nValue,
"pubkey_script": prev_out.scriptPubKey,
}
for prev_out in prevtx.vout
],
},
}
)
outputs: List[bitbox02.BTCOutputType] = []
for output_index, (psbt_out, tx_out) in builtins.enumerate(
zip(psbt.outputs, psbt.tx.vout)
):
_, keypath = find_our_key(psbt_out.hd_keypaths)
is_change = keypath and keypath[-2] == 1
if is_change:
assert keypath is not None
simple_type = get_simple_type(tx_out, psbt_out.redeem_script)
outputs.append(
bitbox02.BTCOutputInternal(
keypath=keypath,
value=tx_out.nValue,
script_config_index=script_config_index_map[simple_type],
)
)
else:
if tx_out.is_p2pkh():
output_type = bitbox02.btc.P2PKH
output_hash = tx_out.scriptPubKey[3:23]
elif is_p2wpkh(tx_out.scriptPubKey):
output_type = bitbox02.btc.P2WPKH
output_hash = tx_out.scriptPubKey[2:]
elif tx_out.is_p2sh():
output_type = bitbox02.btc.P2SH
output_hash = tx_out.scriptPubKey[2:22]
elif is_p2wsh(tx_out.scriptPubKey):
output_type = bitbox02.btc.P2WSH
output_hash = tx_out.scriptPubKey[2:]
else:
raise BadArgumentError(
"Output type not recognized of output {}".format(output_index)
)
outputs.append(
bitbox02.BTCOutputExternal(
output_type=output_type,
output_hash=output_hash,
value=tx_out.nValue,
)
)
assert bip44_account is not None
bip44_network = 1 + HARDENED if self.is_testnet else 0 + HARDENED
sigs = self.init().btc_sign(
bitbox02.btc.TBTC if self.is_testnet else bitbox02.btc.BTC,
[
bitbox02.btc.BTCScriptConfigWithKeypath(
script_config=bitbox02.btc.BTCScriptConfig(
simple_type=bitbox02.btc.BTCScriptConfig.P2WPKH
),
keypath=[84 + HARDENED, bip44_network, bip44_account],
),
bitbox02.btc.BTCScriptConfigWithKeypath(
script_config=bitbox02.btc.BTCScriptConfig(
simple_type=bitbox02.btc.BTCScriptConfig.P2WPKH_P2SH
),
keypath=[49 + HARDENED, bip44_network, bip44_account],
),
],
inputs=inputs,
outputs=outputs,
locktime=psbt.tx.nLockTime,
version=psbt.tx.nVersion,
)
for (_, sig), pubkey, psbt_in in zip(sigs, found_pubkeys, psbt.inputs):
r, s = sig[:32], sig[32:64]
# ser_sig_der() adds SIGHASH_ALL
psbt_in.partial_sigs[pubkey] = ser_sig_der(r, s)
return {"psbt": psbt.serialize()}
def sign_tx(self, tx):
self._check_unlocked()
# Get this devices master key fingerprint
master_key = btc.get_public_node(self.client, [0x80000000],
coin_name="Bitcoin")
master_fp = get_xpub_fingerprint(master_key.xpub)
# Do multiple passes for multisig
passes = 1
p = 0
while p < passes:
# Prepare inputs
inputs = []
to_ignore = (
[]
) # Note down which inputs whose signatures we're going to ignore
for input_num, (psbt_in, txin) in py_enumerate(
list(zip(tx.inputs, tx.tx.vin))):
txinputtype = proto.TxInputType()
# Set the input stuff
txinputtype.prev_hash = ser_uint256(txin.prevout.hash)[::-1]
txinputtype.prev_index = txin.prevout.n
txinputtype.sequence = txin.nSequence
# Detrermine spend type
scriptcode = b""
utxo = None
if psbt_in.witness_utxo:
utxo = psbt_in.witness_utxo
if psbt_in.non_witness_utxo:
if txin.prevout.hash != psbt_in.non_witness_utxo.sha256:
raise BadArgumentError(
"Input {} has a non_witness_utxo with the wrong hash"
.format(input_num))
utxo = psbt_in.non_witness_utxo.vout[txin.prevout.n]
if utxo is None:
continue
scriptcode = utxo.scriptPubKey
# Check if P2SH
p2sh = False
if is_p2sh(scriptcode):
# Look up redeemscript
if len(psbt_in.redeem_script) == 0:
continue
scriptcode = psbt_in.redeem_script
p2sh = True
# Check segwit
is_wit, _, _ = is_witness(scriptcode)
if is_wit:
if p2sh:
txinputtype.script_type = proto.InputScriptType.SPENDP2SHWITNESS
else:
txinputtype.script_type = proto.InputScriptType.SPENDWITNESS
else:
txinputtype.script_type = proto.InputScriptType.SPENDADDRESS
txinputtype.amount = utxo.nValue
# Check if P2WSH
p2wsh = False
if is_p2wsh(scriptcode):
# Look up witnessscript
if len(psbt_in.witness_script) == 0:
continue
scriptcode = psbt_in.witness_script
p2wsh = True
def ignore_input():
txinputtype.address_n = [
0x80000000 | 84,
0x80000000 | (1 if self.is_testnet else 0),
]
txinputtype.multisig = None
txinputtype.script_type = proto.InputScriptType.SPENDWITNESS
inputs.append(txinputtype)
to_ignore.append(input_num)
# Check for multisig
is_ms, multisig = parse_multisig(scriptcode)
if is_ms:
txinputtype.multisig = parse_multisig_xpubs(
tx, psbt_in, multisig)
if not is_wit:
if utxo.is_p2sh:
txinputtype.script_type = (
proto.InputScriptType.SPENDMULTISIG)
else:
# Cannot sign bare multisig, ignore it
ignore_input()
continue
elif not is_ms and not is_wit and not is_p2pkh(scriptcode):
# Cannot sign unknown spk, ignore it
ignore_input()
continue
elif not is_ms and is_wit and p2wsh:
# Cannot sign unknown witness script, ignore it
ignore_input()
continue
# Find key to sign with
found = False # Whether we have found a key to sign with
found_in_sigs = (
False # Whether we have found one of our keys in the signatures
)
our_keys = 0
for key in psbt_in.hd_keypaths.keys():
keypath = psbt_in.hd_keypaths[key]
if keypath[0] == master_fp:
if (key in psbt_in.partial_sigs
): # This key already has a signature
found_in_sigs = True
continue
if (
not found
): # This key does not have a signature and we don't have a key to sign with yet
txinputtype.address_n = keypath[1:]
found = True
our_keys += 1
# Determine if we need to do more passes to sign everything
if our_keys > passes:
passes = our_keys
if (
not found and not found_in_sigs
): # None of our keys were in hd_keypaths or in partial_sigs
# This input is not one of ours
ignore_input()
continue
elif (
not found and found_in_sigs
): # All of our keys are in partial_sigs, ignore whatever signature is produced for this input
ignore_input()
continue
# append to inputs
inputs.append(txinputtype)
# address version byte
if self.is_testnet:
p2pkh_version = b"\x6f"
p2sh_version = b"\xc4"
bech32_hrp = "tb"
else:
p2pkh_version = b"\x00"
p2sh_version = b"\x05"
bech32_hrp = "bc"
# prepare outputs
outputs = []
for i, out in py_enumerate(tx.tx.vout):
txoutput = proto.TxOutputType()
txoutput.amount = out.nValue
txoutput.script_type = proto.OutputScriptType.PAYTOADDRESS
if out.is_p2pkh():
txoutput.address = to_address(out.scriptPubKey[3:23],
p2pkh_version)
elif out.is_p2sh():
txoutput.address = to_address(out.scriptPubKey[2:22],
p2sh_version)
else:
wit, ver, prog = out.is_witness()
if wit:
txoutput.address = bech32.encode(bech32_hrp, ver, prog)
else:
raise BadArgumentError("Output is not an address")
# Add the derivation path for change
psbt_out = tx.outputs[i]
for _, keypath in psbt_out.hd_keypaths.items():
if keypath[0] == master_fp:
wit, ver, prog = out.is_witness()
if out.is_p2pkh():
txoutput.address_n = keypath[1:]
txoutput.address = None
elif wit:
txoutput.script_type = proto.OutputScriptType.PAYTOWITNESS
txoutput.address_n = keypath[1:]
txoutput.address = None
elif out.is_p2sh() and psbt_out.redeem_script:
wit, ver, prog = CTxOut(
0, psbt_out.redeem_script).is_witness()
if wit and len(prog) == 20:
txoutput.script_type = (
proto.OutputScriptType.PAYTOP2SHWITNESS)
txoutput.address_n = keypath[1:]
txoutput.address = None
is_ms, multisig = parse_multisig(
psbt_out.witness_script if wit else psbt_out.
redeem_script)
if is_ms:
txoutput.multisig = parse_multisig_xpubs(
tx, psbt_out, multisig)
# append to outputs
outputs.append(txoutput)
# Prepare prev txs
prevtxs = {}
for psbt_in in tx.inputs:
if psbt_in.non_witness_utxo:
prev = psbt_in.non_witness_utxo
t = proto.TransactionType()
t.version = prev.nVersion
t.lock_time = prev.nLockTime
for vin in prev.vin:
i = proto.TxInputType()
i.prev_hash = ser_uint256(vin.prevout.hash)[::-1]
i.prev_index = vin.prevout.n
i.script_sig = vin.scriptSig
i.sequence = vin.nSequence
t.inputs.append(i)
for vout in prev.vout:
o = proto.TxOutputBinType()
o.amount = vout.nValue
o.script_pubkey = vout.scriptPubKey
t.bin_outputs.append(o)
logging.debug(psbt_in.non_witness_utxo.hash)
prevtxs[ser_uint256(
psbt_in.non_witness_utxo.sha256)[::-1]] = t
# Sign the transaction
tx_details = proto.SignTx()
tx_details.version = tx.tx.nVersion
tx_details.lock_time = tx.tx.nLockTime
signed_tx = btc.sign_tx(self.client, self.coin_name, inputs,
outputs, tx_details, prevtxs)
# Each input has one signature
for input_num, (psbt_in, sig) in py_enumerate(
list(zip(tx.inputs, signed_tx[0]))):
if input_num in to_ignore:
continue
for pubkey in psbt_in.hd_keypaths.keys():
fp = psbt_in.hd_keypaths[pubkey][0]
if fp == master_fp and pubkey not in psbt_in.partial_sigs:
psbt_in.partial_sigs[pubkey] = sig + b"\x01"
break
p += 1
return {"psbt": tx.serialize()}