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usr / local / lib / python3.8 / site-packages / cryptography / hazmat / backends / openssl /

📁 ..
📄 __init__.py(336 B)
📁 __pycache__
📄 aead.py(5.63 KB)
📄 backend.py(103.88 KB)
📄 ciphers.py(8.41 KB)
📄 cmac.py(2.79 KB)
📄 decode_asn1.py(31.57 KB)
📄 dh.py(10 KB)
📄 dsa.py(9.8 KB)
📄 ec.py(11.79 KB)
📄 ed25519.py(5.49 KB)
📄 ed448.py(5.44 KB)
📄 encode_asn1.py(23.51 KB)
📄 hashes.py(3.04 KB)
📄 hmac.py(2.86 KB)
📄 ocsp.py(13.7 KB)
📄 poly1305.py(2.34 KB)
📄 rsa.py(19.12 KB)
📄 utils.py(2.29 KB)
📄 x25519.py(4.38 KB)
📄 x448.py(3.92 KB)
📄 x509.py(21.11 KB)

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 absolute_import, division, print_function

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

class _CMACContext(object):
    def __init__(self, backend, algorithm, ctx=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

algorithm = utils.read_only_property("_algorithm")

def update(self, data):
        res = self._backend._lib.CMAC_Update(self._ctx, data, len(data))
        self._backend.openssl_assert(res == 1)

def finalize(self):
        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):
        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):
        digest = self.finalize()
        if not constant_time.bytes_eq(digest, signature):
            raise InvalidSignature("Signature did not match digest.")

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