async def step4_serialize_inputs(self) -> None:
writers.write_varint(self.serialized_tx, self.tx.inputs_count)
prefix_hash = self.h_prefix.get_digest()
for i_sign in range(self.tx.inputs_count):
progress.advance()
txi_sign = await helpers.request_tx_input(self.tx_req, i_sign, self.coin)
self.wallet_path.check_input(txi_sign)
self.multisig_fingerprint.check_input(txi_sign)
key_sign = self.keychain.derive(txi_sign.address_n)
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, self.coin)
)
else:
raise SigningError("Unsupported input script type")
h_witness = self.create_hash_writer()
writers.write_uint32(
h_witness, self.tx.version | DECRED_SERIALIZE_WITNESS_SIGNING
)
writers.write_varint(h_witness, self.tx.inputs_count)
for ii in range(self.tx.inputs_count):
if ii == i_sign:
writers.write_bytes_prefixed(h_witness, prev_pkscript)
else:
writers.write_varint(h_witness, 0)
witness_hash = writers.get_tx_hash(
h_witness, double=self.coin.sign_hash_double, reverse=False
)
h_sign = self.create_hash_writer()
writers.write_uint32(h_sign, DECRED_SIGHASH_ALL)
writers.write_bytes_fixed(h_sign, prefix_hash, writers.TX_HASH_SIZE)
writers.write_bytes_fixed(h_sign, witness_hash, writers.TX_HASH_SIZE)
sig_hash = writers.get_tx_hash(h_sign, double=self.coin.sign_hash_double)
signature = ecdsa_sign(key_sign, sig_hash)
# serialize input with correct signature
gc.collect()
script_sig = self.input_derive_script(txi_sign, key_sign_pub, signature)
writers.write_tx_input_decred_witness(
self.serialized_tx, txi_sign, script_sig
)
self.set_serialized_signature(i_sign, signature)
def sign_bip143_input(self, txi: TxInputType) -> Tuple[bytes, bytes]:
self.wallet_path.check_input(txi)
self.multisig_fingerprint.check_input(txi)
if txi.amount > self.bip143_in:
raise SigningError(FailureType.ProcessError,
"Transaction has changed during signing")
self.bip143_in -= txi.amount
node = self.keychain.derive(txi.address_n)
public_key = node.public_key()
hash143_hash = self.hash143_preimage_hash(
txi, addresses.ecdsa_hash_pubkey(public_key, self.coin))
signature = ecdsa_sign(node, hash143_hash)
return public_key, signature
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)