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EDITING: 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 annotations

import typing

from cryptography import utils
from cryptography.exceptions import AlreadyFinalized
from cryptography.hazmat.primitives import ciphers

if typing.TYPE_CHECKING:
    from cryptography.hazmat.backends.openssl.cmac import _CMACContext

class CMAC:
    _ctx: typing.Optional[_CMACContext]
    _algorithm: ciphers.BlockCipherAlgorithm

def __init__(
        self,
        algorithm: ciphers.BlockCipherAlgorithm,
        backend: typing.Any = None,
        ctx: typing.Optional[_CMACContext] = None,
    ) -> None:
        if not isinstance(algorithm, ciphers.BlockCipherAlgorithm):
            raise TypeError("Expected instance of BlockCipherAlgorithm.")
        self._algorithm = algorithm

if ctx is None:
            from cryptography.hazmat.backends.openssl.backend import (
                backend as ossl,
            )

self._ctx = ossl.create_cmac_ctx(self._algorithm)
        else:
            self._ctx = ctx

def update(self, data: bytes) -> None:
        if self._ctx is None:
            raise AlreadyFinalized("Context was already finalized.")

utils._check_bytes("data", data)
        self._ctx.update(data)

def finalize(self) -> bytes:
        if self._ctx is None:
            raise AlreadyFinalized("Context was already finalized.")
        digest = self._ctx.finalize()
        self._ctx = None
        return digest

def verify(self, signature: bytes) -> None:
        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) -> CMAC:
        if self._ctx is None:
            raise AlreadyFinalized("Context was already finalized.")
        return CMAC(self._algorithm, ctx=self._ctx.copy())

CANCEL

Name	Type	Size	Modified	Actions
↩ ..	DIR	—	—
📁 __pycache__/	DIR	—	2026-03-17 06:32
📁 asymmetric/	DIR	—	2026-03-17 06:32
📁 ciphers/	DIR	—	2026-03-17 06:32
📁 kdf/	DIR	—	2026-03-17 06:32
📁 serialization/	DIR	—	2026-03-17 06:32
📁 twofactor/	DIR	—	2026-03-17 06:32
📄 __init__.py	PY	180 B	2026-03-14 12:18	EDIT
📄 _asymmetric.py	PY	532 B	2026-03-14 12:18	EDIT
📄 _cipheralgorithm.py	PY	1.1 KB	2026-03-14 12:18	EDIT
📄 _serialization.py	PY	5.1 KB	2026-03-14 12:18	EDIT
📄 cmac.py	PY	2 KB	2026-03-14 12:18	EDIT
📄 constant_time.py	PY	422 B	2026-03-14 12:18	EDIT
📄 hashes.py	PY	5 KB	2026-03-14 12:18	EDIT
📄 hmac.py	PY	423 B	2026-03-14 12:18	EDIT
📄 keywrap.py	PY	5.5 KB	2026-03-14 12:18	EDIT
📄 padding.py	PY	6.1 KB	2026-03-14 12:18	EDIT
📄 poly1305.py	PY	355 B	2026-03-14 12:18	EDIT