# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

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

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

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

"""

__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)