mirror of
https://github.com/thegeeklab/ansible-later.git
synced 2024-11-15 01:30:40 +00:00
66 lines
2.1 KiB
Python
66 lines
2.1 KiB
Python
# 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.exceptions import (
|
|
AlreadyFinalized, UnsupportedAlgorithm, _Reasons
|
|
)
|
|
from cryptography.hazmat.backends.interfaces import CMACBackend
|
|
from cryptography.hazmat.primitives import ciphers, mac
|
|
|
|
|
|
@utils.register_interface(mac.MACContext)
|
|
class CMAC(object):
|
|
def __init__(self, algorithm, backend, ctx=None):
|
|
if not isinstance(backend, CMACBackend):
|
|
raise UnsupportedAlgorithm(
|
|
"Backend object does not implement CMACBackend.",
|
|
_Reasons.BACKEND_MISSING_INTERFACE
|
|
)
|
|
|
|
if not isinstance(algorithm, ciphers.BlockCipherAlgorithm):
|
|
raise TypeError(
|
|
"Expected instance of BlockCipherAlgorithm."
|
|
)
|
|
self._algorithm = algorithm
|
|
|
|
self._backend = backend
|
|
if ctx is None:
|
|
self._ctx = self._backend.create_cmac_ctx(self._algorithm)
|
|
else:
|
|
self._ctx = ctx
|
|
|
|
def update(self, data):
|
|
if self._ctx is None:
|
|
raise AlreadyFinalized("Context was already finalized.")
|
|
|
|
utils._check_bytes("data", data)
|
|
self._ctx.update(data)
|
|
|
|
def finalize(self):
|
|
if self._ctx is None:
|
|
raise AlreadyFinalized("Context was already finalized.")
|
|
digest = self._ctx.finalize()
|
|
self._ctx = None
|
|
return digest
|
|
|
|
def verify(self, signature):
|
|
utils._check_bytes("signature", signature)
|
|
if self._ctx is None:
|
|
raise AlreadyFinalized("Context was already finalized.")
|
|
|
|
ctx, self._ctx = self._ctx, None
|
|
ctx.verify(signature)
|
|
|
|
def copy(self):
|
|
if self._ctx is None:
|
|
raise AlreadyFinalized("Context was already finalized.")
|
|
return CMAC(
|
|
self._algorithm,
|
|
backend=self._backend,
|
|
ctx=self._ctx.copy()
|
|
)
|