async def process_input(self, txi: TxInputType) -> None:
self.wallet_path.add_input(txi)
self.multisig_fingerprint.add_input(txi)
writers.write_tx_input_check(self.h_confirmed, txi)
self.hash143_add_input(txi) # all inputs are included (non-segwit as well)
if not addresses.validate_full_path(txi.address_n, self.coin, txi.script_type):
await helpers.confirm_foreign_address(txi.address_n)
if input_is_segwit(txi):
await self.process_segwit_input(txi)
elif input_is_nonsegwit(txi):
await self.process_nonsegwit_input(txi)
else:
raise SigningError(FailureType.DataError, "Wrong input script type")
def test_tx_input_check(self):
inp = TxInputType(
address_n=[0],
amount=390000,
prev_hash=unhexlify(
"d5f65ee80147b4bcc70b75e4bbf2d7382021b871bd8867ef8fa525ef50864882"
),
prev_index=0,
script_type=InputScriptType.SPENDWITNESS,
sequence=0xffffffff,
script_sig=b"0123456789",
)
b = bytearray()
writers.write_tx_input_check(b, inp)
self.assertEqual(len(b), 32 + 4 + 4 + 4 + 4 + 4 + 8)
for bad_prevhash in (b"", b"x", b"hello", b"x" * 33):
inp.prev_hash = bad_prevhash
self.assertRaises(AssertionError, writers.write_tx_input_check, b, inp)
async def sign_nonsegwit_input(self, i_sign: int) -> None:
# hash of what we are signing with this input
h_sign = self.create_hash_writer()
# should come out the same as h_confirmed, checked before signing the digest
h_check = self.create_hash_writer()
self.write_tx_header(h_sign, self.tx, witness_marker=False)
writers.write_varint(h_sign, self.tx.inputs_count)
for i in range(self.tx.inputs_count):
# STAGE_REQUEST_4_INPUT in legacy
txi = await helpers.request_tx_input(self.tx_req, i, self.coin)
writers.write_tx_input_check(h_check, txi)
if i == i_sign:
self.wallet_path.check_input(txi)
self.multisig_fingerprint.check_input(txi)
# NOTE: wallet_path is checked in write_tx_input_check()
node = self.keychain.derive(txi.address_n, self.coin.curve_name)
key_sign_pub = node.public_key()
# if multisig, do a sanity check to ensure we are signing with a key that is included in the multisig
if txi.multisig:
multisig.multisig_pubkey_index(txi.multisig, key_sign_pub)
# For the signing process the previous UTXO's scriptPubKey is included in h_sign.
if txi.script_type == InputScriptType.SPENDMULTISIG:
script_pubkey = scripts.output_script_multisig(
multisig.multisig_get_pubkeys(txi.multisig), txi.multisig.m,
)
elif txi.script_type == InputScriptType.SPENDADDRESS:
script_pubkey = scripts.output_script_p2pkh(
addresses.ecdsa_hash_pubkey(key_sign_pub, self.coin)
)
else:
raise SigningError(
FailureType.ProcessError, "Unknown transaction type"
)
txi_sign = txi
else:
script_pubkey = bytes()
self.write_tx_input(h_sign, txi, script_pubkey)
writers.write_varint(h_sign, self.tx.outputs_count)
for i in range(self.tx.outputs_count):
# STAGE_REQUEST_4_OUTPUT in legacy
txo = await helpers.request_tx_output(self.tx_req, i, self.coin)
script_pubkey = self.output_derive_script(txo)
self.write_tx_output(h_check, txo, script_pubkey)
self.write_tx_output(h_sign, txo, script_pubkey)
writers.write_uint32(h_sign, self.tx.lock_time)
writers.write_uint32(h_sign, self.get_hash_type())
# check the control digests
if self.h_confirmed.get_digest() != h_check.get_digest():
raise SigningError(
FailureType.ProcessError, "Transaction has changed during signing"
)
# compute the signature from the tx digest
signature = ecdsa_sign(
node, writers.get_tx_hash(h_sign, double=self.coin.sign_hash_double)
)
# serialize input with correct signature
gc.collect()
script_sig = self.input_derive_script(txi_sign, key_sign_pub, signature)
self.write_tx_input(self.serialized_tx, txi_sign, script_sig)
self.set_serialized_signature(i_sign, signature)
async def check_tx_fee(tx: SignTx, keychain: seed.Keychain):
coin = coins.by_name(tx.coin_name)
# h_first is used to make sure the inputs and outputs streamed in Phase 1
# are the same as in Phase 2. it is thus not required to fully hash the
# tx, as the SignTx info is streamed only once
h_first = utils.HashWriter(sha256()) # not a real tx hash
if coin.decred:
hash143 = decred.DecredPrefixHasher(
tx) # pseudo BIP-0143 prefix hashing
tx_ser = TxRequestSerializedType()
elif tx.overwintered:
if tx.version == 3:
hash143 = zcash.Zip143() # ZIP-0143 transaction hashing
elif tx.version == 4:
hash143 = zcash.Zip243() # ZIP-0243 transaction hashing
else:
raise SigningError(
FailureType.DataError,
"Unsupported version for overwintered transaction",
)
else:
hash143 = segwit_bip143.Bip143() # BIP-0143 transaction hashing
multifp = multisig.MultisigFingerprint(
) # control checksum of multisig inputs
weight = tx_weight.TxWeightCalculator(tx.inputs_count, tx.outputs_count)
total_in = 0 # sum of input amounts
segwit_in = 0 # sum of segwit input amounts
total_out = 0 # sum of output amounts
change_out = 0 # change output amount
wallet_path = [] # common prefix of input paths
segwit = {} # dict of booleans stating if input is segwit
# output structures
txo_bin = TxOutputBinType()
tx_req = TxRequest()
tx_req.details = TxRequestDetailsType()
for i in range(tx.inputs_count):
progress.advance()
# STAGE_REQUEST_1_INPUT
txi = await helpers.request_tx_input(tx_req, i)
wallet_path = input_extract_wallet_path(txi, wallet_path)
writers.write_tx_input_check(h_first, txi)
weight.add_input(txi)
hash143.add_prevouts(
txi) # all inputs are included (non-segwit as well)
hash143.add_sequence(txi)
if not addresses.validate_full_path(txi.address_n, coin,
txi.script_type):
await helpers.confirm_foreign_address(txi.address_n)
if txi.multisig:
multifp.add(txi.multisig)
if txi.script_type in (
InputScriptType.SPENDWITNESS,
InputScriptType.SPENDP2SHWITNESS,
):
if not coin.segwit:
raise SigningError(FailureType.DataError,
"Segwit not enabled on this coin")
if not txi.amount:
raise SigningError(FailureType.DataError,
"Segwit input without amount")
segwit[i] = True
segwit_in += txi.amount
total_in += txi.amount
elif txi.script_type in (
InputScriptType.SPENDADDRESS,
InputScriptType.SPENDMULTISIG,
):
if coin.force_bip143 or tx.overwintered:
if not txi.amount:
raise SigningError(FailureType.DataError,
"Expected input with amount")
segwit[i] = False
segwit_in += txi.amount
total_in += txi.amount
else:
segwit[i] = False
total_in += await get_prevtx_output_value(
coin, tx_req, txi.prev_hash, txi.prev_index)
else:
raise SigningError(FailureType.DataError,
"Wrong input script type")
if coin.decred:
w_txi = writers.empty_bytearray(8 if i == 0 else 0 + 9 +
len(txi.prev_hash))
if i == 0: # serializing first input => prepend headers
writers.write_bytes(w_txi, get_tx_header(coin, tx))
writers.write_tx_input_decred(w_txi, txi)
tx_ser.serialized_tx = w_txi
tx_req.serialized = tx_ser
if coin.decred:
hash143.add_output_count(tx)
for o in range(tx.outputs_count):
# STAGE_REQUEST_3_OUTPUT
txo = await helpers.request_tx_output(tx_req, o)
txo_bin.amount = txo.amount
txo_bin.script_pubkey = output_derive_script(txo, coin, keychain)
weight.add_output(txo_bin.script_pubkey)
if change_out == 0 and output_is_change(txo, wallet_path, segwit_in,
multifp):
# output is change and does not need confirmation
change_out = txo.amount
elif not await helpers.confirm_output(txo, coin):
raise SigningError(FailureType.ActionCancelled, "Output cancelled")
if coin.decred:
if txo.decred_script_version is not None and txo.decred_script_version != 0:
raise SigningError(
FailureType.ActionCancelled,
"Cannot send to output with script version != 0",
)
txo_bin.decred_script_version = txo.decred_script_version
w_txo_bin = writers.empty_bytearray(4 + 8 + 2 + 4 +
len(txo_bin.script_pubkey))
if o == 0: # serializing first output => prepend outputs count
writers.write_varint(w_txo_bin, tx.outputs_count)
writers.write_tx_output(w_txo_bin, txo_bin)
tx_ser.serialized_tx = w_txo_bin
tx_req.serialized = tx_ser
hash143.set_last_output_bytes(w_txo_bin)
writers.write_tx_output(h_first, txo_bin)
hash143.add_output(txo_bin)
total_out += txo_bin.amount
fee = total_in - total_out
if fee < 0:
raise SigningError(FailureType.NotEnoughFunds, "Not enough funds")
# fee > (coin.maxfee per byte * tx size)
if fee > (coin.maxfee_kb / 1000) * (weight.get_total() / 4):
if not await helpers.confirm_feeoverthreshold(fee, coin):
raise SigningError(FailureType.ActionCancelled,
"Signing cancelled")
if not await helpers.confirm_total(total_in - change_out, fee, coin):
raise SigningError(FailureType.ActionCancelled, "Total cancelled")
if coin.decred:
hash143.add_locktime_expiry(tx)
return h_first, hash143, segwit, total_in, wallet_path
async def sign_tx(tx: SignTx, keychain: seed.Keychain):
tx = helpers.sanitize_sign_tx(tx)
progress.init(tx.inputs_count, tx.outputs_count)
# Phase 1
h_first, hash143, segwit, authorized_in, wallet_path = await check_tx_fee(
tx, keychain)
# Phase 2
# - sign inputs
# - check that nothing changed
coin = coins.by_name(tx.coin_name)
tx_ser = TxRequestSerializedType()
txo_bin = TxOutputBinType()
tx_req = TxRequest()
tx_req.details = TxRequestDetailsType()
tx_req.serialized = None
if coin.decred:
prefix_hash = hash143.prefix_hash()
for i_sign in range(tx.inputs_count):
progress.advance()
txi_sign = None
key_sign = None
key_sign_pub = None
if segwit[i_sign]:
# STAGE_REQUEST_SEGWIT_INPUT
txi_sign = await helpers.request_tx_input(tx_req, i_sign)
if not input_is_segwit(txi_sign):
raise SigningError(FailureType.ProcessError,
"Transaction has changed during signing")
input_check_wallet_path(txi_sign, wallet_path)
key_sign = keychain.derive(txi_sign.address_n, coin.curve_name)
key_sign_pub = key_sign.public_key()
txi_sign.script_sig = input_derive_script(coin, txi_sign,
key_sign_pub)
w_txi = writers.empty_bytearray(7 + len(txi_sign.prev_hash) + 4 +
len(txi_sign.script_sig) + 4)
if i_sign == 0: # serializing first input => prepend headers
writers.write_bytes(w_txi, get_tx_header(coin, tx, True))
writers.write_tx_input(w_txi, txi_sign)
tx_ser.serialized_tx = w_txi
tx_req.serialized = tx_ser
elif coin.force_bip143 or tx.overwintered:
# STAGE_REQUEST_SEGWIT_INPUT
txi_sign = await helpers.request_tx_input(tx_req, i_sign)
input_check_wallet_path(txi_sign, wallet_path)
is_bip143 = (txi_sign.script_type == InputScriptType.SPENDADDRESS
or txi_sign.script_type
== InputScriptType.SPENDMULTISIG)
if not is_bip143 or txi_sign.amount > authorized_in:
raise SigningError(FailureType.ProcessError,
"Transaction has changed during signing")
authorized_in -= txi_sign.amount
key_sign = keychain.derive(txi_sign.address_n, coin.curve_name)
key_sign_pub = key_sign.public_key()
hash143_hash = hash143.preimage_hash(
coin,
tx,
txi_sign,
addresses.ecdsa_hash_pubkey(key_sign_pub, coin),
get_hash_type(coin),
)
# if multisig, check if signing with a key that is included in multisig
if txi_sign.multisig:
multisig.multisig_pubkey_index(txi_sign.multisig, key_sign_pub)
signature = ecdsa_sign(key_sign, hash143_hash)
tx_ser.signature_index = i_sign
tx_ser.signature = signature
# serialize input with correct signature
txi_sign.script_sig = input_derive_script(coin, txi_sign,
key_sign_pub, signature)
w_txi_sign = writers.empty_bytearray(5 + len(txi_sign.prev_hash) +
4 + len(txi_sign.script_sig) +
4)
if i_sign == 0: # serializing first input => prepend headers
writers.write_bytes(w_txi_sign, get_tx_header(coin, tx))
writers.write_tx_input(w_txi_sign, txi_sign)
tx_ser.serialized_tx = w_txi_sign
tx_req.serialized = tx_ser
elif coin.decred:
txi_sign = await helpers.request_tx_input(tx_req, i_sign)
input_check_wallet_path(txi_sign, wallet_path)
key_sign = keychain.derive(txi_sign.address_n, coin.curve_name)
key_sign_pub = key_sign.public_key()
if txi_sign.script_type == InputScriptType.SPENDMULTISIG:
prev_pkscript = scripts.output_script_multisig(
multisig.multisig_get_pubkeys(txi_sign.multisig),
txi_sign.multisig.m,
)
elif txi_sign.script_type == InputScriptType.SPENDADDRESS:
prev_pkscript = scripts.output_script_p2pkh(
addresses.ecdsa_hash_pubkey(key_sign_pub, coin))
else:
raise ValueError("Unknown input script type")
h_witness = utils.HashWriter(blake256())
writers.write_uint32(
h_witness,
tx.version | decred.DECRED_SERIALIZE_WITNESS_SIGNING)
writers.write_varint(h_witness, tx.inputs_count)
for ii in range(tx.inputs_count):
if ii == i_sign:
writers.write_varint(h_witness, len(prev_pkscript))
writers.write_bytes(h_witness, prev_pkscript)
else:
writers.write_varint(h_witness, 0)
witness_hash = writers.get_tx_hash(h_witness,
double=coin.sign_hash_double,
reverse=False)
h_sign = utils.HashWriter(blake256())
writers.write_uint32(h_sign, decred.DECRED_SIGHASHALL)
writers.write_bytes(h_sign, prefix_hash)
writers.write_bytes(h_sign, witness_hash)
sig_hash = writers.get_tx_hash(h_sign,
double=coin.sign_hash_double)
signature = ecdsa_sign(key_sign, sig_hash)
tx_ser.signature_index = i_sign
tx_ser.signature = signature
# serialize input with correct signature
txi_sign.script_sig = input_derive_script(coin, txi_sign,
key_sign_pub, signature)
w_txi_sign = writers.empty_bytearray(
8 + 4 +
len(hash143.get_last_output_bytes()) if i_sign == 0 else 0 +
16 + 4 + len(txi_sign.script_sig))
if i_sign == 0:
writers.write_bytes(w_txi_sign,
hash143.get_last_output_bytes())
writers.write_uint32(w_txi_sign, tx.lock_time)
writers.write_uint32(w_txi_sign, tx.expiry)
writers.write_varint(w_txi_sign, tx.inputs_count)
writers.write_tx_input_decred_witness(w_txi_sign, txi_sign)
tx_ser.serialized_tx = w_txi_sign
tx_req.serialized = tx_ser
else:
# hash of what we are signing with this input
h_sign = utils.HashWriter(sha256())
# same as h_first, checked before signing the digest
h_second = utils.HashWriter(sha256())
if tx.overwintered:
writers.write_uint32(
h_sign, tx.version
| zcash.OVERWINTERED) # nVersion | fOverwintered
writers.write_uint32(h_sign,
tx.version_group_id) # nVersionGroupId
else:
writers.write_uint32(h_sign, tx.version) # nVersion
if tx.timestamp:
writers.write_uint32(h_sign, tx.timestamp)
writers.write_varint(h_sign, tx.inputs_count)
for i in range(tx.inputs_count):
# STAGE_REQUEST_4_INPUT
txi = await helpers.request_tx_input(tx_req, i)
input_check_wallet_path(txi, wallet_path)
writers.write_tx_input_check(h_second, txi)
if i == i_sign:
txi_sign = txi
key_sign = keychain.derive(txi.address_n, coin.curve_name)
key_sign_pub = key_sign.public_key()
# for the signing process the script_sig is equal
# to the previous tx's scriptPubKey (P2PKH) or a redeem script (P2SH)
if txi_sign.script_type == InputScriptType.SPENDMULTISIG:
txi_sign.script_sig = scripts.output_script_multisig(
multisig.multisig_get_pubkeys(txi_sign.multisig),
txi_sign.multisig.m,
)
elif txi_sign.script_type == InputScriptType.SPENDADDRESS:
txi_sign.script_sig = scripts.output_script_p2pkh(
addresses.ecdsa_hash_pubkey(key_sign_pub, coin))
if coin.bip115:
txi_sign.script_sig += scripts.script_replay_protection_bip115(
txi_sign.prev_block_hash_bip115,
txi_sign.prev_block_height_bip115,
)
else:
raise SigningError(FailureType.ProcessError,
"Unknown transaction type")
else:
txi.script_sig = bytes()
writers.write_tx_input(h_sign, txi)
writers.write_varint(h_sign, tx.outputs_count)
for o in range(tx.outputs_count):
# STAGE_REQUEST_4_OUTPUT
txo = await helpers.request_tx_output(tx_req, o)
txo_bin.amount = txo.amount
txo_bin.script_pubkey = output_derive_script(
txo, coin, keychain)
writers.write_tx_output(h_second, txo_bin)
writers.write_tx_output(h_sign, txo_bin)
writers.write_uint32(h_sign, tx.lock_time)
if tx.overwintered:
writers.write_uint32(h_sign, tx.expiry) # expiryHeight
writers.write_varint(h_sign, 0) # nJoinSplit
writers.write_uint32(h_sign, get_hash_type(coin))
# check the control digests
if writers.get_tx_hash(h_first,
False) != writers.get_tx_hash(h_second):
raise SigningError(FailureType.ProcessError,
"Transaction has changed during signing")
# if multisig, check if signing with a key that is included in multisig
if txi_sign.multisig:
multisig.multisig_pubkey_index(txi_sign.multisig, key_sign_pub)
# compute the signature from the tx digest
signature = ecdsa_sign(
key_sign,
writers.get_tx_hash(h_sign, double=coin.sign_hash_double))
tx_ser.signature_index = i_sign
tx_ser.signature = signature
# serialize input with correct signature
txi_sign.script_sig = input_derive_script(coin, txi_sign,
key_sign_pub, signature)
w_txi_sign = writers.empty_bytearray(5 + len(txi_sign.prev_hash) +
4 + len(txi_sign.script_sig) +
4)
if i_sign == 0: # serializing first input => prepend headers
writers.write_bytes(w_txi_sign, get_tx_header(coin, tx))
writers.write_tx_input(w_txi_sign, txi_sign)
tx_ser.serialized_tx = w_txi_sign
tx_req.serialized = tx_ser
if coin.decred:
return await helpers.request_tx_finish(tx_req)
for o in range(tx.outputs_count):
progress.advance()
# STAGE_REQUEST_5_OUTPUT
txo = await helpers.request_tx_output(tx_req, o)
txo_bin.amount = txo.amount
txo_bin.script_pubkey = output_derive_script(txo, coin, keychain)
# serialize output
w_txo_bin = writers.empty_bytearray(5 + 8 + 5 +
len(txo_bin.script_pubkey) + 4)
if o == 0: # serializing first output => prepend outputs count
writers.write_varint(w_txo_bin, tx.outputs_count)
writers.write_tx_output(w_txo_bin, txo_bin)
tx_ser.signature_index = None
tx_ser.signature = None
tx_ser.serialized_tx = w_txo_bin
tx_req.serialized = tx_ser
any_segwit = True in segwit.values()
for i in range(tx.inputs_count):
progress.advance()
if segwit[i]:
# STAGE_REQUEST_SEGWIT_WITNESS
txi = await helpers.request_tx_input(tx_req, i)
input_check_wallet_path(txi, wallet_path)
if not input_is_segwit(txi) or txi.amount > authorized_in:
raise SigningError(FailureType.ProcessError,
"Transaction has changed during signing")
authorized_in -= txi.amount
key_sign = keychain.derive(txi.address_n, coin.curve_name)
key_sign_pub = key_sign.public_key()
hash143_hash = hash143.preimage_hash(
coin,
tx,
txi,
addresses.ecdsa_hash_pubkey(key_sign_pub, coin),
get_hash_type(coin),
)
signature = ecdsa_sign(key_sign, hash143_hash)
if txi.multisig:
# find out place of our signature based on the pubkey
signature_index = multisig.multisig_pubkey_index(
txi.multisig, key_sign_pub)
witness = scripts.witness_p2wsh(txi.multisig, signature,
signature_index,
get_hash_type(coin))
else:
witness = scripts.witness_p2wpkh(signature, key_sign_pub,
get_hash_type(coin))
tx_ser.serialized_tx = witness
tx_ser.signature_index = i
tx_ser.signature = signature
elif any_segwit:
tx_ser.serialized_tx = bytearray(
1) # empty witness for non-segwit inputs
tx_ser.signature_index = None
tx_ser.signature = None
tx_req.serialized = tx_ser
writers.write_uint32(tx_ser.serialized_tx, tx.lock_time)
if tx.overwintered:
if tx.version == 3:
writers.write_uint32(tx_ser.serialized_tx,
tx.expiry) # expiryHeight
writers.write_varint(tx_ser.serialized_tx, 0) # nJoinSplit
elif tx.version == 4:
writers.write_uint32(tx_ser.serialized_tx,
tx.expiry) # expiryHeight
writers.write_uint64(tx_ser.serialized_tx, 0) # valueBalance
writers.write_varint(tx_ser.serialized_tx, 0) # nShieldedSpend
writers.write_varint(tx_ser.serialized_tx, 0) # nShieldedOutput
writers.write_varint(tx_ser.serialized_tx, 0) # nJoinSplit
else:
raise SigningError(
FailureType.DataError,
"Unsupported version for overwintered transaction",
)
await helpers.request_tx_finish(tx_req)
