Current File : //var/opt/nydus/ops/oscrypto/util.py
# coding: utf-8
from __future__ import unicode_literals, division, absolute_import, print_function
import sys
from ._errors import pretty_message
from ._types import type_name, byte_cls
if sys.platform == 'darwin':
from ._mac.util import rand_bytes
elif sys.platform == 'win32':
from ._win.util import rand_bytes
else:
from ._openssl.util import rand_bytes
__all__ = [
'constant_compare',
'rand_bytes',
]
def constant_compare(a, b):
"""
Compares two byte strings in constant time to see if they are equal
:param a:
The first byte string
:param b:
The second byte string
:return:
A boolean if the two byte strings are equal
"""
if not isinstance(a, byte_cls):
raise TypeError(pretty_message(
'''
a must be a byte string, not %s
''',
type_name(a)
))
if not isinstance(b, byte_cls):
raise TypeError(pretty_message(
'''
b must be a byte string, not %s
''',
type_name(b)
))
if len(a) != len(b):
return False
if sys.version_info < (3,):
a = [ord(char) for char in a]
b = [ord(char) for char in b]
result = 0
for x, y in zip(a, b):
result |= x ^ y
return result == 0
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