z3c.bcrypt

z3c.bcrypt provides zope.password compatible “password manager” utilities that use bcrypt (or alternatively pbkdf2) encoding for storing passwords.

Both encoding schemes are implemented in the cryptacular library that is a dependency for this package.

Using z3c.bcrypt

>>> from zope.interface.verify import verifyObject
>>> from zope.password.interfaces import IPasswordManager
>>> from z3c.bcrypt import BcryptPasswordManager
>>> manager = BcryptPasswordManager()
>>> verifyObject(IPasswordManager, manager)
True

>>> password = u"right \N{CYRILLIC CAPITAL LETTER A}"

>>> encoded = manager.encodePassword(password)
>>> encoded
'$2a$...'
>>> manager.checkPassword(encoded, password)
True
>>> manager.checkPassword(encoded, password + u"wrong")
False

>>> from z3c.bcrypt import PBKDF2PasswordManager
>>> manager = PBKDF2PasswordManager()
>>> verifyObject(IPasswordManager, manager)
True

>>> encoded = manager.encodePassword(password)
>>> encoded
u'$p5k2$...'
>>> manager.checkPassword(encoded, password)
True
>>> manager.checkPassword(encoded, password + u"wrong")
False

>>> # A previously encoded password, should be decodable even if the
>>> # current encoding of the same password is different::
>>> previouslyencoded = (
...     '$p5k2$1000$LgAFPIlc9CgrlSaxHyTUMA='
...     '=$IuUYplhMkR4qCl8-ONRVjEgJNwE=')
>>> encoded == previouslyencoded
False
>>> manager.checkPassword(previouslyencoded , password)
True

Excessively long “passwords” will take up a lot of computation time that can be used as a DOS attack vector. The password managers in z3c.bcrypt will only use the first 4096 characters of the incoming password for checking.

This is inspired by:

https://www.djangoproject.com/weblog/2013/sep/15/security/

This test would take significantly longer if the 4096 length limit would not be in place. XXX how to test that reliably?

>>> incomming = '$p5k2$1000$' + 'a' * 1024 * 1024 * 100  # lot of data.
>>> manager.checkPassword(encoded, incomming)
False

Changelog of z3c.bcrypt