59 lines
2.1 KiB
Python
59 lines
2.1 KiB
Python
# combo - content management system
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# Copyright (C) 2015-2018 Entr'ouvert
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#
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# This program is free software: you can redistribute it and/or modify it
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# under the terms of the GNU Affero General Public License as published
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# by the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import binascii
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from Cryptodome.Cipher import AES
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from Cryptodome.Protocol.KDF import PBKDF2
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from Cryptodome import Random
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from django.utils import six
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from django.utils.encoding import force_text
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class DecryptionError(Exception):
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pass
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def aes_hex_encrypt(key, data):
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'''Generate an AES key from any key material using PBKDF2, and encrypt data using CFB mode. A
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new IV is generated each time, the IV is also used as salt for PBKDF2.
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'''
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iv = Random.get_random_bytes(2) * 8
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aes_key = PBKDF2(key, iv)
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aes = AES.new(aes_key, AES.MODE_CFB, iv)
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crypted = aes.encrypt(data)
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return force_text(b'%s%s' % (binascii.hexlify(iv[:2]), binascii.hexlify(crypted)))
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def aes_hex_decrypt(key, payload, raise_on_error=True):
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'''Decrypt data encrypted with aes_base64_encrypt'''
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try:
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iv, crypted = payload[:4], payload[4:]
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except (ValueError, TypeError):
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if raise_on_error:
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raise DecryptionError('bad payload')
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return None
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try:
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iv = binascii.unhexlify(iv) * 8
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crypted = binascii.unhexlify(crypted)
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except (TypeError, binascii.Error):
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if raise_on_error:
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raise DecryptionError('incorrect hexadecimal encoding')
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return None
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aes_key = PBKDF2(key, iv)
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aes = AES.new(aes_key, AES.MODE_CFB, iv)
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return force_text(aes.decrypt(crypted), 'utf-8')
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