1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function
from cryptography import utils
from cryptography.hazmat._der import (
DERReader, INTEGER, SEQUENCE, encode_der, encode_der_integer
)
from cryptography.hazmat.primitives import hashes
def decode_dss_signature(signature):
seq = DERReader(signature).read_single_element(SEQUENCE)
r = seq.read_element(INTEGER).as_integer()
s = seq.read_element(INTEGER).as_integer()
seq.check_empty()
return r, s
def encode_dss_signature(r, s):
return encode_der(
SEQUENCE,
encode_der(INTEGER, encode_der_integer(r)),
encode_der(INTEGER, encode_der_integer(s)),
)
class Prehashed(object):
def __init__(self, algorithm):
if not isinstance(algorithm, hashes.HashAlgorithm):
raise TypeError("Expected instance of HashAlgorithm.")
self._algorithm = algorithm
self._digest_size = algorithm.digest_size
digest_size = utils.read_only_property("_digest_size")
|
