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ecc: use libsecp256k1 for signature conversions

Browse source 
(instead of python-ecdsa)
This commit is contained in:
SomberNight 2020-02-06 19:13:21 +01:00
parent ad408ea832
commit ab0c70e291
No known key found for this signature in database
GPG key ID: B33B5F232C6271E9
2 changed files with 56 additions and 9 deletions
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59
electrum/ecc.py
View file

@ -65,32 +65,73 @@ def string_to_number(b: bytes) -> int:
return int.from_bytes(b, byteorder='big', signed=False)
def sig_string_from_der_sig(der_sig: bytes, order=CURVE_ORDER) -> bytes: # TODO use libsecp?
r, s = ecdsa.util.sigdecode_der(der_sig, order)
return ecdsa.util.sigencode_string(r, s, order)
def sig_string_from_der_sig(der_sig: bytes, order=CURVE_ORDER) -> bytes:
r, s = get_r_and_s_from_der_sig(der_sig)
return sig_string_from_r_and_s(r, s)
def der_sig_from_sig_string(sig_string: bytes, order=CURVE_ORDER) -> bytes:
r, s = ecdsa.util.sigdecode_string(sig_string, order)
return ecdsa.util.sigencode_der_canonize(r, s, order)
r, s = get_r_and_s_from_sig_string(sig_string)
return der_sig_from_r_and_s(r, s)
def der_sig_from_r_and_s(r: int, s: int, order=CURVE_ORDER) -> bytes:
return ecdsa.util.sigencode_der_canonize(r, s, order)
sig_string = (int.to_bytes(r, length=32, byteorder="big") +
int.to_bytes(s, length=32, byteorder="big"))
sig = create_string_buffer(64)
ret = _libsecp256k1.secp256k1_ecdsa_signature_parse_compact(_libsecp256k1.ctx, sig, sig_string)
if not ret:
raise Exception("Bad signature")
ret = _libsecp256k1.secp256k1_ecdsa_signature_normalize(_libsecp256k1.ctx, sig, sig)
der_sig = create_string_buffer(80) # this much space should be enough
der_sig_size = c_size_t(len(der_sig))
ret = _libsecp256k1.secp256k1_ecdsa_signature_serialize_der(_libsecp256k1.ctx, der_sig, byref(der_sig_size), sig)
if not ret:
raise Exception("failed to serialize DER sig")
der_sig_size = der_sig_size.value
return bytes(der_sig)[:der_sig_size]
def get_r_and_s_from_der_sig(der_sig: bytes, order=CURVE_ORDER) -> Tuple[int, int]:
r, s = ecdsa.util.sigdecode_der(der_sig, order)
assert isinstance(der_sig, bytes)
sig = create_string_buffer(64)
ret = _libsecp256k1.secp256k1_ecdsa_signature_parse_der(_libsecp256k1.ctx, sig, der_sig, len(der_sig))
if not ret:
raise Exception("Bad signature")
ret = _libsecp256k1.secp256k1_ecdsa_signature_normalize(_libsecp256k1.ctx, sig, sig)
compact_signature = create_string_buffer(64)
_libsecp256k1.secp256k1_ecdsa_signature_serialize_compact(_libsecp256k1.ctx, compact_signature, sig)
r = int.from_bytes(compact_signature[:32], byteorder="big")
s = int.from_bytes(compact_signature[32:], byteorder="big")
return r, s
def get_r_and_s_from_sig_string(sig_string: bytes, order=CURVE_ORDER) -> Tuple[int, int]:
r, s = ecdsa.util.sigdecode_string(sig_string, order)
if not (isinstance(sig_string, bytes) and len(sig_string) == 64):
raise Exception("sig_string must be bytes, and 64 bytes exactly")
sig = create_string_buffer(64)
ret = _libsecp256k1.secp256k1_ecdsa_signature_parse_compact(_libsecp256k1.ctx, sig, sig_string)
if not ret:
raise Exception("Bad signature")
ret = _libsecp256k1.secp256k1_ecdsa_signature_normalize(_libsecp256k1.ctx, sig, sig)
compact_signature = create_string_buffer(64)
_libsecp256k1.secp256k1_ecdsa_signature_serialize_compact(_libsecp256k1.ctx, compact_signature, sig)
r = int.from_bytes(compact_signature[:32], byteorder="big")
s = int.from_bytes(compact_signature[32:], byteorder="big")
return r, s
def sig_string_from_r_and_s(r: int, s: int, order=CURVE_ORDER) -> bytes:
return ecdsa.util.sigencode_string_canonize(r, s, order)
sig_string = (int.to_bytes(r, length=32, byteorder="big") +
int.to_bytes(s, length=32, byteorder="big"))
sig = create_string_buffer(64)
ret = _libsecp256k1.secp256k1_ecdsa_signature_parse_compact(_libsecp256k1.ctx, sig, sig_string)
if not ret:
raise Exception("Bad signature")
ret = _libsecp256k1.secp256k1_ecdsa_signature_normalize(_libsecp256k1.ctx, sig, sig)
compact_signature = create_string_buffer(64)
_libsecp256k1.secp256k1_ecdsa_signature_serialize_compact(_libsecp256k1.ctx, compact_signature, sig)
return bytes(compact_signature)
def point_to_ser(point, compressed=True) -> Optional[bytes]: # TODO rm?

6
electrum/ecc_fast.py
View file

@ -79,6 +79,12 @@ def load_library():
secp256k1.secp256k1_ecdsa_signature_serialize_compact.argtypes = [c_void_p, c_char_p, c_char_p]
secp256k1.secp256k1_ecdsa_signature_serialize_compact.restype = c_int
secp256k1.secp256k1_ecdsa_signature_parse_der.argtypes = [c_void_p, c_char_p, c_char_p, c_size_t]
secp256k1.secp256k1_ecdsa_signature_parse_der.restype = c_int
secp256k1.secp256k1_ecdsa_signature_serialize_der.argtypes = [c_void_p, c_char_p, c_void_p, c_char_p]
secp256k1.secp256k1_ecdsa_signature_serialize_der.restype = c_int
secp256k1.secp256k1_ec_pubkey_tweak_mul.argtypes = [c_void_p, c_char_p, c_char_p]
secp256k1.secp256k1_ec_pubkey_tweak_mul.restype = c_int