root / snf-cyclades-app / synnefo / db / aes_encrypt.py @ 19b2c29d
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1 | 91884d63 | Giorgos Korfiatis | # Copyright 2012, 2013 GRNET S.A. All rights reserved.
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2 | 91884d63 | Giorgos Korfiatis | #
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3 | 91884d63 | Giorgos Korfiatis | # Redistribution and use in source and binary forms, with or without
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4 | 91884d63 | Giorgos Korfiatis | # modification, are permitted provided that the following conditions
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5 | 91884d63 | Giorgos Korfiatis | # are met:
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6 | 91884d63 | Giorgos Korfiatis | #
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7 | 91884d63 | Giorgos Korfiatis | # 1. Redistributions of source code must retain the above copyright
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8 | 91884d63 | Giorgos Korfiatis | # notice, this list of conditions and the following disclaimer.
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9 | 91884d63 | Giorgos Korfiatis | #
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10 | 91884d63 | Giorgos Korfiatis | # 2. Redistributions in binary form must reproduce the above copyright
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11 | 91884d63 | Giorgos Korfiatis | # notice, this list of conditions and the following disclaimer in the
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12 | 91884d63 | Giorgos Korfiatis | # documentation and/or other materials provided with the distribution.
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13 | 91884d63 | Giorgos Korfiatis | #
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14 | 91884d63 | Giorgos Korfiatis | # THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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15 | 91884d63 | Giorgos Korfiatis | # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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16 | 91884d63 | Giorgos Korfiatis | # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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17 | 91884d63 | Giorgos Korfiatis | # ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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18 | 91884d63 | Giorgos Korfiatis | # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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19 | 91884d63 | Giorgos Korfiatis | # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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20 | 91884d63 | Giorgos Korfiatis | # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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21 | 91884d63 | Giorgos Korfiatis | # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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22 | 91884d63 | Giorgos Korfiatis | # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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23 | 91884d63 | Giorgos Korfiatis | # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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24 | 91884d63 | Giorgos Korfiatis | # SUCH DAMAGE.
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25 | 91884d63 | Giorgos Korfiatis | #
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26 | 91884d63 | Giorgos Korfiatis | # The views and conclusions contained in the software and documentation are
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27 | 91884d63 | Giorgos Korfiatis | # those of the authors and should not be interpreted as representing official
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28 | 91884d63 | Giorgos Korfiatis | # policies, either expressed or implied, of GRNET S.A.
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29 | 91884d63 | Giorgos Korfiatis | |
30 | 30e0ed74 | Christos Stavrakakis | from binascii import b2a_base64, a2b_base64 |
31 | 30e0ed74 | Christos Stavrakakis | from Crypto.Cipher import AES |
32 | 3dbd9457 | Christos Stavrakakis | from Crypto import Random |
33 | 30e0ed74 | Christos Stavrakakis | from random import choice |
34 | 30e0ed74 | Christos Stavrakakis | from string import letters, digits |
35 | ca8b1c21 | Christos Stavrakakis | from synnefo.settings import SECRET_ENCRYPTION_KEY |
36 | 30e0ed74 | Christos Stavrakakis | |
37 | 30e0ed74 | Christos Stavrakakis | |
38 | 30e0ed74 | Christos Stavrakakis | DB_ENCRYPTED_FIELD_PREFIX = 'encrypted'
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39 | 30e0ed74 | Christos Stavrakakis | SALT_LEN = 8
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40 | 30e0ed74 | Christos Stavrakakis | |
41 | 30e0ed74 | Christos Stavrakakis | |
42 | 30e0ed74 | Christos Stavrakakis | def _pad_secret(secret, blocksize=32, padding='}'): |
43 | 0224049a | Christos Stavrakakis | len_secret = len(secret)
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44 | 0224049a | Christos Stavrakakis | if len_secret > 32: |
45 | 0224049a | Christos Stavrakakis | raise ValueError('Encryption key must be smaller than 32 bytes') |
46 | 0224049a | Christos Stavrakakis | if not len_secret in (16, 24, 32): |
47 | 30e0ed74 | Christos Stavrakakis | return secret + (blocksize - len(secret)) * padding |
48 | 30e0ed74 | Christos Stavrakakis | return secret
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49 | 30e0ed74 | Christos Stavrakakis | |
50 | 30e0ed74 | Christos Stavrakakis | |
51 | 3dbd9457 | Christos Stavrakakis | def encrypt(s, iv): |
52 | 3dbd9457 | Christos Stavrakakis | obj = AES.new(_pad_secret(SECRET_ENCRYPTION_KEY), AES.MODE_CFB, iv) |
53 | 30e0ed74 | Christos Stavrakakis | return obj.encrypt(s)
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54 | 30e0ed74 | Christos Stavrakakis | |
55 | 30e0ed74 | Christos Stavrakakis | |
56 | 3dbd9457 | Christos Stavrakakis | def decrypt(s, iv): |
57 | 3dbd9457 | Christos Stavrakakis | obj = AES.new(_pad_secret(SECRET_ENCRYPTION_KEY), AES.MODE_CFB, iv) |
58 | 30e0ed74 | Christos Stavrakakis | return obj.decrypt(s)
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59 | 30e0ed74 | Christos Stavrakakis | |
60 | 30e0ed74 | Christos Stavrakakis | |
61 | 30e0ed74 | Christos Stavrakakis | def encrypt_db_charfield(plaintext): |
62 | 68b952f9 | Christos Stavrakakis | if not plaintext: |
63 | 30e0ed74 | Christos Stavrakakis | return plaintext
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64 | 30e0ed74 | Christos Stavrakakis | salt = "".join([choice(letters + digits) for i in xrange(SALT_LEN)]) |
65 | 30e0ed74 | Christos Stavrakakis | |
66 | 3dbd9457 | Christos Stavrakakis | iv = Random.get_random_bytes(16)
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67 | 30e0ed74 | Christos Stavrakakis | plaintext = "%s%s" % (salt, plaintext)
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68 | 30e0ed74 | Christos Stavrakakis | # Encrypt and convert to binary
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69 | 3dbd9457 | Christos Stavrakakis | ciphertext = b2a_base64(encrypt(plaintext, iv)) |
70 | 3dbd9457 | Christos Stavrakakis | iv = b2a_base64(iv) |
71 | 30e0ed74 | Christos Stavrakakis | # Append prefix,salt and return encoded value
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72 | 3dbd9457 | Christos Stavrakakis | final = '%s:%s:%s$%s' % (DB_ENCRYPTED_FIELD_PREFIX, iv, salt, ciphertext)
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73 | 30e0ed74 | Christos Stavrakakis | return final.encode('utf8') |
74 | 30e0ed74 | Christos Stavrakakis | |
75 | 30e0ed74 | Christos Stavrakakis | |
76 | 30e0ed74 | Christos Stavrakakis | def decrypt_db_charfield(ciphertext): |
77 | 68b952f9 | Christos Stavrakakis | if not ciphertext: |
78 | 30e0ed74 | Christos Stavrakakis | return ciphertext
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79 | 30e0ed74 | Christos Stavrakakis | has_prefix = ciphertext.startswith(DB_ENCRYPTED_FIELD_PREFIX + ':')
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80 | 30e0ed74 | Christos Stavrakakis | if not has_prefix: # Non-encoded value |
81 | 30e0ed74 | Christos Stavrakakis | return ciphertext
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82 | 30e0ed74 | Christos Stavrakakis | else:
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83 | 3dbd9457 | Christos Stavrakakis | _, iv, ciphertext = ciphertext.split(':')
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84 | 30e0ed74 | Christos Stavrakakis | |
85 | 30e0ed74 | Christos Stavrakakis | pure_salt, encrypted = ciphertext.split('$')
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86 | 3dbd9457 | Christos Stavrakakis | iv = a2b_base64(iv) |
87 | 30e0ed74 | Christos Stavrakakis | |
88 | 3dbd9457 | Christos Stavrakakis | plaintext = decrypt(a2b_base64(encrypted), iv) |
89 | 30e0ed74 | Christos Stavrakakis | |
90 | 30e0ed74 | Christos Stavrakakis | salt = plaintext[:SALT_LEN] |
91 | 30e0ed74 | Christos Stavrakakis | plaintext = plaintext[SALT_LEN:] |
92 | 30e0ed74 | Christos Stavrakakis | |
93 | 30e0ed74 | Christos Stavrakakis | if salt != pure_salt:
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94 | 8d5795b4 | Christos Stavrakakis | # Cannot decrtypt password
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95 | 8d5795b4 | Christos Stavrakakis | raise CorruptedPassword("Cannot decrypt password. Check the key") |
96 | 30e0ed74 | Christos Stavrakakis | else:
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97 | 30e0ed74 | Christos Stavrakakis | return plaintext
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98 | 30e0ed74 | Christos Stavrakakis | |
99 | 30e0ed74 | Christos Stavrakakis | |
100 | 30e0ed74 | Christos Stavrakakis | class CorruptedPassword(Exception): |
101 | 30e0ed74 | Christos Stavrakakis | pass |