Esempio n. 1
0
def shadow(password):
	"""Generate a random salt and return a new hash for the password."""
	if isinstance(password, str): password = password.encode('utf-8')
	salt = b64encode(urandom(SALT_LENGTH))
	p    = b64encode(ensureBytes(pbkdf2_bin(password, salt, COST_FACTOR, KEY_LENGTH, getattr(hashlib, HASH_FUNCTION))))
	return 'PBKDF2${}${}${}${}'.format(
		HASH_FUNCTION,
		COST_FACTOR,
		ensureString(salt, "ascii"),
		ensureString(p,    "ascii"),
	)
Esempio n. 2
0
def verify(password, shadow):
	"""Check a password against an existing hash."""
	password = ensureString(password)
	algorithm, hash_function, cost_factor, salt, hash_a = shadow.split('$')
	assert algorithm == 'PBKDF2'
	salt   = ensureBytes(salt)
	hash_a = b64decode(hash_a)
	hash_b = pbkdf2_bin(password, salt, int(cost_factor), len(hash_a), getattr(hashlib, hash_function))
	assert len(hash_a) == len(hash_b)  # we requested this from pbkdf2_bin()
	# Same as "return hash_a == hash_b" but takes a constant time.
	# See http://carlos.bueno.org/2011/10/timing.html
	diff = 0
	for char_a, char_b in zip(hash_a, hash_b):
		if IS_PYTHON3:
			diff |= char_a ^ ord(char_b)
		else:
			diff |= ord(char_a) ^ ord(char_b)
	return diff == 0
Esempio n. 3
0
def pbkdf2_bin(data, salt, iterations=1000, keylen=24, hashfunc=None):
	"""Returns a binary digest for the PBKDF2 hash algorithm of `data`
	with the given `salt`.  It iterates `iterations` time and produces a
	key of `keylen` bytes.  By default SHA-1 is used as hash function,
	a different hashlib `hashfunc` can be provided.
	"""
	hashfunc = hashfunc or hashlib.sha1
	if type(data) is unicode: data = data.encode()
	mac = hmac.new(data, None, hashfunc)
	def _pseudorandom(x, mac=mac):
		h = mac.copy()
		h.update(ensureBytes(x))
		if not IS_PYTHON3:
			return list(map(ord, h.digest()))
		else:
			return list(h.digest())
	buf = []
	for block in range(1, -(-keylen // mac.digest_size) + 1):
		rv = u = _pseudorandom(salt + _pack_int(block))
		for i in range(iterations - 1):
			u = _pseudorandom(''.join(map(chr, u)))
			rv = starmap(xor, zip(rv, u))
		buf.extend(rv)
	return ensureString(''.join(map(chr, buf))[:keylen])