pbkdf2 implementation

gistfile1.py

import hmac
import struct
import hashlib
import binascii


def force_bytes(s, encoding='utf-8', strings_only=False, errors='strict'):
    """
Similar to smart_bytes, except that lazy instances are resolved to
strings, rather than kept as lazy objects.

If strings_only is True, don't convert (some) non-string-like objects.
"""
    return s.decode('utf-8', errors).encode(encoding, errors)


def pbkdf2(password, salt, iterations, dklen=0, digest=None):
    assert iterations > 0
    if not digest:
        digest = hashlib.sha256
    password = force_bytes(password)
    salt = force_bytes(salt)
    hlen = digest().digest_size
    if not dklen:
        dklen = hlen
    if dklen > (2 ** 32 - 1) * hlen:
        raise OverflowError('dklen too big')
    l = -(-dklen // hlen)
    r = dklen - (l - 1) * hlen

    hex_format_string = "%%0%ix" % (hlen * 2)

    inner, outer = digest(), digest()
    if len(password) > inner.block_size:
        password = digest(password).digest()
    password += b'\x00' * (inner.block_size - len(password))
    inner.update(password.translate(hmac.trans_36))
    outer.update(password.translate(hmac.trans_5C))

    def F(i):
        u = salt + struct.pack(b'>I', i)
        result = 0
        for j in xrange(int(iterations)):
            dig1, dig2 = inner.copy(), outer.copy()
            dig1.update(u)
            dig2.update(dig1.digest())
            u = dig2.hexdigest()
            result ^= _bin_to_long(u)
        return _long_to_bin(result, hex_format_string)

    T = [F(x) for x in range(1, l)]
    return b''.join(T) + F(l)[:r]


def _bin_to_long(x):
    """
Convert a binary string into a long integer

This is a clever optimization for fast xor vector math
"""
    return int(binascii.hexlify(x), 16)


def _long_to_bin(x, hex_format_string):
    """
Convert a long integer into a binary string.
hex_format_string is like "%020x" for padding 10 characters.
"""
    return binascii.unhexlify((hex_format_string % x).encode('ascii'))

if __name__ == "__main__":
    path = "/home/dmakogon/Documents/Trove/Trove-confs/templates/mysql/heat.template"
    ololo = pbkdf2('lol', 'lol', 5, dklen=32)
    print str(ololo.decode('ascii'))