/usr/lib/python2.7/dist-packages/cryptography/hazmat/primitives/ciphers/modes.py is in python-cryptography 0.6.1-1+deb8u1.
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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
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