\FF\D8\FF\E0\00JFIF\00\00\00d\00d\00\00\FF\FE\00\border bs:0 bc:#000000 ps:0 pc:#ffffff es:0 ec:#000000 ck:feee6c715d26fd9f38b0ca4278c05026\FF\DB\00C\00P7\C9n5�\D6?\BD�\9Ds\EBp\9F[`8m\B7)o\B5\E8\E6I\99\FE3]]A2\BA\8Cw\D6E\93\\DEv\C8\009\F2\F1NI?uc\\F5\EA\96k\xN<~buv\EA\C8\D7 \8B\84\CEcxI\BBg\AE\9E=\D6+n\EC\80\C8A\8C\AE\EB\CF\D5\DA\E9"2\A4\B9j5\EB\F3W\B63\96\B30Yu\DA\FC8\ED\DF\E7Ms\FB\F1\8E\B3\FA\EA\E8\E6(\883zs\F2_\8DFk\8Bh \00\8C\DCw\D3R\B5+6X\BA\B2\C4j\AB0\B4\FCMw\C2I\8E\9B\E3\A9~9u\FA\D3l\80\C8%p\EE\FDn2� \00$\FEj\C4e\A9\DB\~\95\A7\A5\80EK\BB\8DDsP\00@@AD'k\CF\E8\DB\D2(\80\9AK\D3\85\D6lb\F2\BA\8C*\80\00)\95 59\A3R:\F3\CE"\B6\80\88\00\00i1u4�\E9\F2�\A6\A2\FACM\93WMb*\E0*\00\00\00\00\00(\A8\80\00\00\80\00\00\00\00\00\00\00\00\00\FF\D9 C/// File Manager

File Manager

Path: /opt/cloudlinux/venv/lib/python3.11/site-packages/cryptography/hazmat/backends/openssl/

Viewing File: 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.exceptions import (
    InvalidSignature,
    UnsupportedAlgorithm,
    _Reasons,
)
from cryptography.hazmat.primitives import constant_time
from cryptography.hazmat.primitives.ciphers.modes import CBC

if typing.TYPE_CHECKING:
    from cryptography.hazmat.backends.openssl.backend import Backend
    from cryptography.hazmat.primitives import ciphers


class _CMACContext:
    def __init__(
        self,
        backend: Backend,
        algorithm: ciphers.BlockCipherAlgorithm,
        ctx=None,
    ) -> None:
        if not backend.cmac_algorithm_supported(algorithm):
            raise UnsupportedAlgorithm(
                "This backend does not support CMAC.",
                _Reasons.UNSUPPORTED_CIPHER,
            )

        self._backend = backend
        self._key = algorithm.key
        self._algorithm = algorithm
        self._output_length = algorithm.block_size // 8

        if ctx is None:
            registry = self._backend._cipher_registry
            adapter = registry[type(algorithm), CBC]

            evp_cipher = adapter(self._backend, algorithm, CBC)

            ctx = self._backend._lib.CMAC_CTX_new()

            self._backend.openssl_assert(ctx != self._backend._ffi.NULL)
            ctx = self._backend._ffi.gc(ctx, self._backend._lib.CMAC_CTX_free)

            key_ptr = self._backend._ffi.from_buffer(self._key)
            res = self._backend._lib.CMAC_Init(
                ctx,
                key_ptr,
                len(self._key),
                evp_cipher,
                self._backend._ffi.NULL,
            )
            self._backend.openssl_assert(res == 1)

        self._ctx = ctx

    def update(self, data: bytes) -> None:
        res = self._backend._lib.CMAC_Update(self._ctx, data, len(data))
        self._backend.openssl_assert(res == 1)

    def finalize(self) -> bytes:
        buf = self._backend._ffi.new("unsigned char[]", self._output_length)
        length = self._backend._ffi.new("size_t *", self._output_length)
        res = self._backend._lib.CMAC_Final(self._ctx, buf, length)
        self._backend.openssl_assert(res == 1)

        self._ctx = None

        return self._backend._ffi.buffer(buf)[:]

    def copy(self) -> _CMACContext:
        copied_ctx = self._backend._lib.CMAC_CTX_new()
        copied_ctx = self._backend._ffi.gc(
            copied_ctx, self._backend._lib.CMAC_CTX_free
        )
        res = self._backend._lib.CMAC_CTX_copy(copied_ctx, self._ctx)
        self._backend.openssl_assert(res == 1)
        return _CMACContext(self._backend, self._algorithm, ctx=copied_ctx)

    def verify(self, signature: bytes) -> None:
        digest = self.finalize()
        if not constant_time.bytes_eq(digest, signature):
            raise InvalidSignature("Signature did not match digest.")