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ecc: small clean-up

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SomberNight 2019-09-18 02:09:15 +02:00
parent 1669dd9782
commit 30bb7dd6f4
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GPG key ID: B33B5F232C6271E9
1 changed files with 13 additions and 12 deletions
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25
electrum/ecc.py
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@ -25,7 +25,7 @@
import base64 import base64
import hashlib import hashlib
from typing import Union, Tuple from typing import Union, Tuple, Optional
import ecdsa import ecdsa
from ecdsa.ecdsa import curve_secp256k1, generator_secp256k1 from ecdsa.ecdsa import curve_secp256k1, generator_secp256k1
@ -83,12 +83,12 @@ def sig_string_from_r_and_s(r: int, s: int, order=CURVE_ORDER) -> bytes:
return ecdsa.util.sigencode_string_canonize(r, s, order) return ecdsa.util.sigencode_string_canonize(r, s, order)
def point_to_ser(P, compressed=True) -> bytes: def point_to_ser(point, compressed=True) -> Optional[bytes]:
if isinstance(P, tuple): if isinstance(point, tuple):
assert len(P) == 2, 'unexpected point: %s' % P assert len(point) == 2, f'unexpected point: {point}'
x, y = P x, y = point
else: else:
x, y = P.x(), P.y() x, y = point.x(), point.y()
if x is None or y is None: # infinity if x is None or y is None: # infinity
return None return None
if compressed: if compressed:
@ -96,7 +96,7 @@ def point_to_ser(P, compressed=True) -> bytes:
return bfh('04'+('%064x' % x)+('%064x' % y)) return bfh('04'+('%064x' % x)+('%064x' % y))
def get_y_coord_from_x(x: int, odd: bool=True) -> int: def get_y_coord_from_x(x: int, *, odd: bool) -> int:
curve = curve_secp256k1 curve = curve_secp256k1
_p = curve.p() _p = curve.p()
_a = curve.a() _a = curve.a()
@ -117,7 +117,8 @@ def ser_to_point(ser: bytes) -> Tuple[int, int]:
if ser[0] == 0x04: if ser[0] == 0x04:
return string_to_number(ser[1:33]), string_to_number(ser[33:]) return string_to_number(ser[1:33]), string_to_number(ser[33:])
x = string_to_number(ser[1:]) x = string_to_number(ser[1:])
return x, get_y_coord_from_x(x, ser[0] == 0x03) odd = ser[0] == 0x03
return x, get_y_coord_from_x(x, odd=odd)
def _ser_to_python_ecdsa_point(ser: bytes) -> ecdsa.ellipticcurve.Point: def _ser_to_python_ecdsa_point(ser: bytes) -> ecdsa.ellipticcurve.Point:
@ -182,7 +183,7 @@ class _PubkeyForPointAtInfinity:
class ECPubkey(object): class ECPubkey(object):
def __init__(self, b: bytes): def __init__(self, b: Optional[bytes]):
if b is not None: if b is not None:
assert_bytes(b) assert_bytes(b)
point = _ser_to_python_ecdsa_point(b) point = _ser_to_python_ecdsa_point(b)
@ -434,8 +435,8 @@ class ECPrivkey(ECPubkey):
sig65, recid = bruteforce_recid(sig_string) sig65, recid = bruteforce_recid(sig_string)
return sig65 return sig65
def decrypt_message(self, encrypted: Tuple[str, bytes], magic: bytes=b'BIE1') -> bytes: def decrypt_message(self, encrypted: Union[str, bytes], magic: bytes=b'BIE1') -> bytes:
encrypted = base64.b64decode(encrypted) encrypted = base64.b64decode(encrypted) # type: bytes
if len(encrypted) < 85: if len(encrypted) < 85:
raise Exception('invalid ciphertext: length') raise Exception('invalid ciphertext: length')
magic_found = encrypted[:4] magic_found = encrypted[:4]
@ -446,7 +447,7 @@ class ECPrivkey(ECPubkey):
raise Exception('invalid ciphertext: invalid magic bytes') raise Exception('invalid ciphertext: invalid magic bytes')
try: try:
ecdsa_point = _ser_to_python_ecdsa_point(ephemeral_pubkey_bytes) ecdsa_point = _ser_to_python_ecdsa_point(ephemeral_pubkey_bytes)
except AssertionError as e: except InvalidECPointException as e:
raise Exception('invalid ciphertext: invalid ephemeral pubkey') from e raise Exception('invalid ciphertext: invalid ephemeral pubkey') from e
if not ecdsa.ecdsa.point_is_valid(generator_secp256k1, ecdsa_point.x(), ecdsa_point.y()): if not ecdsa.ecdsa.point_is_valid(generator_secp256k1, ecdsa_point.x(), ecdsa_point.y()):
raise Exception('invalid ciphertext: invalid ephemeral pubkey') raise Exception('invalid ciphertext: invalid ephemeral pubkey')