ilvalle
141 lines
5.0 KiB
Python
141 lines
5.0 KiB
Python
# -*- coding: utf-8 -*-
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"""
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pbkdf2
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~~~~~~
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This module implements pbkdf2 for Python. It also has some basic
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tests that ensure that it works. The implementation is straightforward
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and uses stdlib only stuff and can be easily be copy/pasted into
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your favourite application.
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Use this as replacement for bcrypt that does not need a c implementation
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of a modified blowfish crypto algo.
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Example usage:
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>>> pbkdf2_hex('what i want to hash', 'the random salt')
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'fa7cc8a2b0a932f8e6ea42f9787e9d36e592e0c222ada6a9'
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How to use this:
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1. Use a constant time string compare function to compare the stored hash
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with the one you're generating::
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def safe_str_cmp(a, b):
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if len(a) != len(b):
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return False
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rv = 0
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for x, y in izip(a, b):
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rv |= ord(x) ^ ord(y)
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return rv == 0
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2. Use `os.urandom` to generate a proper salt of at least 8 byte.
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Use a unique salt per hashed password.
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3. Store ``algorithm$salt:costfactor$hash`` in the database so that
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you can upgrade later easily to a different algorithm if you need
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one. For instance ``PBKDF2-256$thesalt:10000$deadbeef...``.
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:copyright: (c) Copyright 2011 by Armin Ronacher.
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:license: BSD, see LICENSE for more details.
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"""
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from __future__ import print_function
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import hmac
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try:
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from hashlib import sha1
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except ImportError:
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# hashlib not available. Use the old sha module.
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import sha as sha1
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from struct import Struct
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from operator import xor
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from itertools import izip, starmap
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from collections import deque
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_pack_int = Struct('>I').pack
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try:
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from Crypto.Util.strxor import strxor
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except ImportError:
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def strxor(a, b):
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return ''.join(chr(xor(ord(x), ord(y))) for x,y in izip(a, b))
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def pbkdf2_hex(data, salt, iterations=1000, keylen=24, hashfunc=None):
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"""Like :func:`pbkdf2_bin` but returns a hex encoded string."""
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return pbkdf2_bin(data, salt, iterations, keylen, hashfunc).encode('hex')
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def pbkdf2_bin(data, salt, iterations=1000, keylen=24, hashfunc=None):
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"""Returns a binary digest for the PBKDF2 hash algorithm of `data`
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with the given `salt`. It iterates `iterations` time and produces a
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key of `keylen` bytes. By default SHA-1 is used as hash function,
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a different hashlib `hashfunc` can be provided.
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"""
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hashfunc = hashfunc or sha1
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mac = hmac.new(data, None, hashfunc)
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def _pseudorandom(x, mac=mac):
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h = mac.copy()
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h.update(x)
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return h.digest()
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buf = deque()
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for block in xrange(1, -(-keylen // mac.digest_size) + 1):
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rv = u = _pseudorandom(salt + _pack_int(block))
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for i in xrange(iterations - 1):
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u = _pseudorandom(u)
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rv = strxor(rv, u)
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buf.extend(rv)
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return ''.join(buf)[:keylen]
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def test():
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failed = []
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def check(data, salt, iterations, keylen, expected):
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rv = pbkdf2_hex(data, salt, iterations, keylen)
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if rv != expected:
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print('Test failed:')
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print(' Expected: %s' % expected)
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print(' Got: %s' % rv)
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print(' Parameters:')
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print(' data=%s' % data)
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print(' salt=%s' % salt)
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print(' iterations=%d' % iterations)
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print()
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failed.append(1)
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# From RFC 6070
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check('password', 'salt', 1, 20,
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'0c60c80f961f0e71f3a9b524af6012062fe037a6')
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check('password', 'salt', 2, 20,
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'ea6c014dc72d6f8ccd1ed92ace1d41f0d8de8957')
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check('password', 'salt', 4096, 20,
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'4b007901b765489abead49d926f721d065a429c1')
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check('passwordPASSWORDpassword', 'saltSALTsaltSALTsaltSALTsaltSALTsalt',
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4096, 25, '3d2eec4fe41c849b80c8d83662c0e44a8b291a964cf2f07038')
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check('pass\x00word', 'sa\x00lt', 4096, 16,
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'56fa6aa75548099dcc37d7f03425e0c3')
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# This one is from the RFC but it just takes for ages
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check('password', 'salt', 16777216, 20,
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'eefe3d61cd4da4e4e9945b3d6ba2158c2634e984')
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# From Crypt-PBKDF2
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check('password', 'ATHENA.MIT.EDUraeburn', 1, 16,
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'cdedb5281bb2f801565a1122b2563515')
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check('password', 'ATHENA.MIT.EDUraeburn', 1, 32,
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'cdedb5281bb2f801565a1122b25635150ad1f7a04bb9f3a333ecc0e2e1f70837')
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check('password', 'ATHENA.MIT.EDUraeburn', 2, 16,
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'01dbee7f4a9e243e988b62c73cda935d')
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check('password', 'ATHENA.MIT.EDUraeburn', 2, 32,
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'01dbee7f4a9e243e988b62c73cda935da05378b93244ec8f48a99e61ad799d86')
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check('password', 'ATHENA.MIT.EDUraeburn', 1200, 32,
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'5c08eb61fdf71e4e4ec3cf6ba1f5512ba7e52ddbc5e5142f708a31e2e62b1e13')
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check('X' * 64, 'pass phrase equals block size', 1200, 32,
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'139c30c0966bc32ba55fdbf212530ac9c5ec59f1a452f5cc9ad940fea0598ed1')
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check('X' * 65, 'pass phrase exceeds block size', 1200, 32,
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'9ccad6d468770cd51b10e6a68721be611a8b4d282601db3b36be9246915ec82a')
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raise SystemExit(bool(failed))
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if __name__ == '__main__':
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test()
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