42 lines
1.2 KiB
Python
42 lines
1.2 KiB
Python
# coding: utf-8
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"""PBKDF2 implementation suitable for GOST R 34.11-94/34.11-2012.
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This implementation is based on Python 3.5.2 source code's one.
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PyGOST does not register itself in hashlib anyway, so use it instead.
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"""
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from pygost.utils import bytes2long
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from pygost.utils import long2bytes
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from pygost.utils import strxor
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from pygost.utils import xrange
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def pbkdf2(hasher, password, salt, iterations, dklen):
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"""PBKDF2 implementation suitable for GOST R 34.11-94/34.11-2012
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"""
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inner = hasher()
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outer = hasher()
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password = password + b"\x00" * (inner.block_size - len(password))
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inner.update(strxor(password, len(password) * b"\x36"))
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outer.update(strxor(password, len(password) * b"\x5C"))
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def prf(msg):
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icpy = inner.copy()
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ocpy = outer.copy()
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icpy.update(msg)
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ocpy.update(icpy.digest())
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return ocpy.digest()
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dkey = b""
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loop = 1
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while len(dkey) < dklen:
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prev = prf(salt + long2bytes(loop, 4))
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rkey = bytes2long(prev)
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for _ in xrange(iterations - 1):
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prev = prf(prev)
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rkey ^= bytes2long(prev)
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loop += 1
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dkey += long2bytes(rkey, inner.digest_size)
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return dkey[:dklen]
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