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//lib64/python3.6/site-packages/cryptography/hazmat/primitives/cmac.py

# 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 import _get_backend
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=None, ctx=None):
        backend = _get_backend(backend)
        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()
        )

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asymmetric DIR	-	drwxr-xr-x	2025-08-29 23:02:24	Edit Download recursive recursive
ciphers DIR	-	drwxr-xr-x	2025-08-29 23:02:24	Edit Download recursive recursive
kdf DIR	-	drwxr-xr-x	2025-08-29 23:02:24	Edit Download recursive recursive
serialization DIR	-	drwxr-xr-x	2025-08-29 23:02:24	Edit Download recursive recursive
twofactor DIR	-	drwxr-xr-x	2025-08-29 23:02:24	Edit Download recursive recursive
__pycache__ DIR	-	drwxr-xr-x	2025-08-29 23:02:24	Edit Download recursive recursive
cmac.py	2.13 KB	lrw-r--r--	2025-08-26 10:01:14	Edit Download recursive recursive
constant_time.py	430 B	lrw-r--r--	2020-10-28 03:11:40	Edit Download recursive recursive
hashes.py	6.17 KB	lrw-r--r--	2020-10-28 03:11:40	Edit Download recursive recursive
hmac.py	2.30 KB	lrw-r--r--	2025-08-26 10:01:14	Edit Download recursive recursive
keywrap.py	5.60 KB	lrw-r--r--	2020-10-28 03:11:40	Edit Download recursive recursive
mac.py	884 B	lrw-r--r--	2025-08-26 10:01:14	Edit Download recursive recursive
padding.py	5.61 KB	lrw-r--r--	2020-10-28 03:11:40	Edit Download recursive recursive
poly1305.py	1.64 KB	lrw-r--r--	2020-10-28 03:11:40	Edit Download recursive recursive
__init__.py	246 B	lrw-r--r--	2020-10-28 03:11:40	Edit Download recursive recursive

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