tMerge pull request #5494 from SomberNight/tx_signing_perf_20190708 - electrum - Electrum Bitcoin wallet
HTML git clone https://git.parazyd.org/electrum
DIR Log
DIR Files
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DIR Submodules
---
DIR commit 261c492c37d45193b808b9c91c6b3e5549dc9c42
DIR parent a14016275b028bb53e9a2151bb27bdb84d063d07
HTML Author: ThomasV <thomasv@electrum.org>
Date: Tue, 9 Jul 2019 17:41:56 +0200
Merge pull request #5494 from SomberNight/tx_signing_perf_20190708
ttransaction: segwit input signing was doing quadratic hashing
Diffstat:
M electrum/transaction.py | 35 +++++++++++++++++++++++++-------
1 file changed, 28 insertions(+), 7 deletions(-)
---
DIR diff --git a/electrum/transaction.py b/electrum/transaction.py
t@@ -86,6 +86,12 @@ class TxOutputHwInfo(NamedTuple):
script_type: str
+class BIP143SharedTxDigestFields(NamedTuple):
+ hashPrevouts: str
+ hashSequence: str
+ hashOutputs: str
+
+
class BCDataStream(object):
"""Workalike python implementation of Bitcoin's CDataStream class."""
t@@ -958,7 +964,18 @@ class Transaction:
s += script
return s
- def serialize_preimage(self, txin_index: int) -> str:
+ def _calc_bip143_shared_txdigest_fields(self) -> BIP143SharedTxDigestFields:
+ inputs = self.inputs()
+ outputs = self.outputs()
+ hashPrevouts = bh2u(sha256d(bfh(''.join(self.serialize_outpoint(txin) for txin in inputs))))
+ hashSequence = bh2u(sha256d(bfh(''.join(int_to_hex(txin.get('sequence', 0xffffffff - 1), 4) for txin in inputs))))
+ hashOutputs = bh2u(sha256d(bfh(''.join(self.serialize_output(o) for o in outputs))))
+ return BIP143SharedTxDigestFields(hashPrevouts=hashPrevouts,
+ hashSequence=hashSequence,
+ hashOutputs=hashOutputs)
+
+ def serialize_preimage(self, txin_index: int, *,
+ bip143_shared_txdigest_fields: BIP143SharedTxDigestFields = None) -> str:
nVersion = int_to_hex(self.version, 4)
nHashType = int_to_hex(1, 4) # SIGHASH_ALL
nLocktime = int_to_hex(self.locktime, 4)
t@@ -966,9 +983,11 @@ class Transaction:
outputs = self.outputs()
txin = inputs[txin_index]
if self.is_segwit_input(txin):
- hashPrevouts = bh2u(sha256d(bfh(''.join(self.serialize_outpoint(txin) for txin in inputs))))
- hashSequence = bh2u(sha256d(bfh(''.join(int_to_hex(txin.get('sequence', 0xffffffff - 1), 4) for txin in inputs))))
- hashOutputs = bh2u(sha256d(bfh(''.join(self.serialize_output(o) for o in outputs))))
+ if bip143_shared_txdigest_fields is None:
+ bip143_shared_txdigest_fields = self._calc_bip143_shared_txdigest_fields()
+ hashPrevouts = bip143_shared_txdigest_fields.hashPrevouts
+ hashSequence = bip143_shared_txdigest_fields.hashSequence
+ hashOutputs = bip143_shared_txdigest_fields.hashOutputs
outpoint = self.serialize_outpoint(txin)
preimage_script = self.get_preimage_script(txin)
scriptCode = var_int(len(preimage_script) // 2) + preimage_script
t@@ -1129,6 +1148,7 @@ class Transaction:
def sign(self, keypairs) -> None:
# keypairs: (x_)pubkey -> secret_bytes
+ bip143_shared_txdigest_fields = self._calc_bip143_shared_txdigest_fields()
for i, txin in enumerate(self.inputs()):
pubkeys, x_pubkeys = self.get_sorted_pubkeys(txin)
for j, (pubkey, x_pubkey) in enumerate(zip(pubkeys, x_pubkeys)):
t@@ -1142,14 +1162,15 @@ class Transaction:
continue
_logger.info(f"adding signature for {_pubkey}")
sec, compressed = keypairs.get(_pubkey)
- sig = self.sign_txin(i, sec)
+ sig = self.sign_txin(i, sec, bip143_shared_txdigest_fields=bip143_shared_txdigest_fields)
self.add_signature_to_txin(i, j, sig)
_logger.info(f"is_complete {self.is_complete()}")
self.raw = self.serialize()
- def sign_txin(self, txin_index, privkey_bytes) -> str:
- pre_hash = sha256d(bfh(self.serialize_preimage(txin_index)))
+ def sign_txin(self, txin_index, privkey_bytes, *, bip143_shared_txdigest_fields=None) -> str:
+ pre_hash = sha256d(bfh(self.serialize_preimage(txin_index,
+ bip143_shared_txdigest_fields=bip143_shared_txdigest_fields)))
privkey = ecc.ECPrivkey(privkey_bytes)
sig = privkey.sign_transaction(pre_hash)
sig = bh2u(sig) + '01'