def pbkdf2(password, salt, iterations, dklen=0, digest=None): """ Implements PBKDF2 with the same API as Django's existing implementation, using the stdlib. This is used in Python 2.7.8+ and 3.4+. """ if digest is None: digest = hashlib.sha256 if not dklen: dklen = None password = force_bytes(password) salt = force_bytes(salt) return hashlib.pbkdf2_hmac( digest().name, password, salt, iterations, dklen)
def pbkdf2(password, salt, iterations, dklen=0, digest=None): """ Implements PBKDF2 as defined in RFC 2898, section 5.2 HMAC+SHA256 is used as the default pseudo random function. As of 2014, 100,000 iterations was the recommended default which took 100ms on a 2.7Ghz Intel i7 with an optimized implementation. This is probably the bare minimum for security given 1000 iterations was recommended in 2001. This code is very well optimized for CPython and is about five times slower than OpenSSL's implementation. Look in django.contrib.auth.hashers for the present default, it is lower than the recommended 100,000 because of the performance difference between this and an optimized implementation. """ 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 range(int(iterations)): dig1, dig2 = inner.copy(), outer.copy() dig1.update(u) dig2.update(dig1.digest()) u = dig2.digest() 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 constant_time_compare(val1, val2): return hmac.compare_digest(force_bytes(val1), force_bytes(val2))