"""Simple cryptographic routines, based on python-crypto.

:organization: Logilab

:copyright: 2009-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

from pickle import dumps, loads

from base64 import b64encode, b64decode

from Crypto.Cipher import Blowfish

_CYPHERERS = {}

def _cypherer(seed):

    try:

        return _CYPHERERS[seed]

    except KeyError:

        _CYPHERERS[seed] = Blowfish.new(seed, Blowfish.MODE_ECB)

        return _CYPHERERS[seed]

def encrypt(data, seed):

    string = dumps(data)

    string = string + '*' * (8 - len(string) % 8)

    string = b64encode(_cypherer(seed).encrypt(string))

    return unicode(string)

def decrypt(string, seed):

    # pickle ignores trailing characters so we do not need to strip them off

    string = _cypherer(seed).decrypt(b64decode(string))

    return loads(string)