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
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import absolute_import, division, print_function
from cryptography import utils
from cryptography.hazmat.primitives import interfaces
def _check_iv_length(mode, algorithm):
if len(mode.initialization_vector) * 8 != algorithm.block_size:
raise ValueError("Invalid IV size ({0}) for {1}.".format(
len(mode.initialization_vector), mode.name
))
@utils.register_interface(interfaces.Mode)
@utils.register_interface(interfaces.ModeWithInitializationVector)
class CBC(object):
name = "CBC"
def __init__(self, initialization_vector):
self.initialization_vector = initialization_vector
validate_for_algorithm = _check_iv_length
@utils.register_interface(interfaces.Mode)
class ECB(object):
name = "ECB"
def validate_for_algorithm(self, algorithm):
pass
@utils.register_interface(interfaces.Mode)
@utils.register_interface(interfaces.ModeWithInitializationVector)
class OFB(object):
name = "OFB"
def __init__(self, initialization_vector):
self.initialization_vector = initialization_vector
validate_for_algorithm = _check_iv_length
@utils.register_interface(interfaces.Mode)
@utils.register_interface(interfaces.ModeWithInitializationVector)
class CFB(object):
name = "CFB"
def __init__(self, initialization_vector):
self.initialization_vector = initialization_vector
validate_for_algorithm = _check_iv_length
@utils.register_interface(interfaces.Mode)
@utils.register_interface(interfaces.ModeWithInitializationVector)
class CFB8(object):
name = "CFB8"
def __init__(self, initialization_vector):
self.initialization_vector = initialization_vector
validate_for_algorithm = _check_iv_length
@utils.register_interface(interfaces.Mode)
@utils.register_interface(interfaces.ModeWithNonce)
class CTR(object):
name = "CTR"
def __init__(self, nonce):
self.nonce = nonce
def validate_for_algorithm(self, algorithm):
if len(self.nonce) * 8 != algorithm.block_size:
raise ValueError("Invalid nonce size ({0}) for {1}.".format(
len(self.nonce), self.name
))
@utils.register_interface(interfaces.Mode)
@utils.register_interface(interfaces.ModeWithInitializationVector)
@utils.register_interface(interfaces.ModeWithAuthenticationTag)
class GCM(object):
name = "GCM"
def __init__(self, initialization_vector, tag=None, min_tag_length=16):
# len(initialization_vector) must in [1, 2 ** 64), but it's impossible
# to actually construct a bytes object that large, so we don't check
# for it
if min_tag_length < 4:
raise ValueError("min_tag_length must be >= 4")
if tag is not None and len(tag) < min_tag_length:
raise ValueError(
"Authentication tag must be {0} bytes or longer.".format(
min_tag_length)
)
self.initialization_vector = initialization_vector
self.tag = tag
def validate_for_algorithm(self, algorithm):
pass
|
