Viewing file:  constant_time.py (1.11 KB) -rw-r--r--
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# 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
import hmac
import warnings
from cryptography import utils
from cryptography.hazmat.bindings._constant_time import lib
if hasattr(hmac, "compare_digest"):
def bytes_eq(a, b):
if not isinstance(a, bytes) or not isinstance(b, bytes):
raise TypeError("a and b must be bytes.")
return hmac.compare_digest(a, b)
else:
warnings.warn(
"Support for your Python version is deprecated. The next version of "
"cryptography will remove support. Please upgrade to a release "
"(2.7.7+) that supports hmac.compare_digest as soon as possible.",
utils.PersistentlyDeprecated2018,
)
def bytes_eq(a, b):
if not isinstance(a, bytes) or not isinstance(b, bytes):
raise TypeError("a and b must be bytes.")
return lib.Cryptography_constant_time_bytes_eq(
a, len(a), b, len(b)
) == 1
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