55 lines
1.5 KiB
Python
55 lines
1.5 KiB
Python
import string
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import binascii
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from random import choice
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from Crypto.Cipher import AES
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from django.db import models
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from django.conf import settings
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EOD = '`%EofD%`' # This should be something that will not occur in strings
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def genstring(length=16, chars=string.printable):
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return ''.join([choice(chars) for i in range(length)])
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def encrypt(key, s):
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obj = AES.new(key)
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datalength = len(s) + len(EOD)
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if datalength < 16:
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saltlength = 16 - datalength
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else:
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saltlength = 16 - datalength % 16
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ss = ''.join([s, EOD, genstring(saltlength)])
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return obj.encrypt(ss)
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def decrypt(key, s):
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obj = AES.new(key)
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ss = obj.decrypt(s)
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return ss.split(bytes(EOD, 'utf-8'))[0]
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class AESEncryptedField(models.CharField):
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def save_form_data(self, instance, data):
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setattr(instance, self.name,
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binascii.b2a_base64(encrypt(settings.AES_KEY, data)))
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def to_python(self, value):
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if value is None:
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return None
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return decrypt(settings.AES_KEY,
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binascii.a2b_base64(value)).decode('utf-8')
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def from_db_value(self, value, expression, connection, *args):
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if value is None:
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return value
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return decrypt(settings.AES_KEY,
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binascii.a2b_base64(value)).decode('utf-8')
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def get_prep_value(self, value):
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return binascii.b2a_base64(encrypt(
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settings.AES_KEY,
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value
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))
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