root / snf-cyclades-app / synnefo / db / aes_encrypt.py @ f32e8021
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1 | 30e0ed74 | Christos Stavrakakis | from binascii import b2a_base64, a2b_base64 |
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2 | 30e0ed74 | Christos Stavrakakis | from Crypto.Cipher import AES |
3 | 3dbd9457 | Christos Stavrakakis | from Crypto import Random |
4 | 30e0ed74 | Christos Stavrakakis | from random import choice |
5 | 30e0ed74 | Christos Stavrakakis | from string import letters, digits |
6 | ca8b1c21 | Christos Stavrakakis | from synnefo.settings import SECRET_ENCRYPTION_KEY |
7 | 30e0ed74 | Christos Stavrakakis | |
8 | 30e0ed74 | Christos Stavrakakis | |
9 | 30e0ed74 | Christos Stavrakakis | DB_ENCRYPTED_FIELD_PREFIX = 'encrypted'
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10 | 30e0ed74 | Christos Stavrakakis | SALT_LEN = 8
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11 | 30e0ed74 | Christos Stavrakakis | |
12 | 30e0ed74 | Christos Stavrakakis | |
13 | 30e0ed74 | Christos Stavrakakis | def _pad_secret(secret, blocksize=32, padding='}'): |
14 | 0224049a | Christos Stavrakakis | len_secret = len(secret)
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15 | 0224049a | Christos Stavrakakis | if len_secret > 32: |
16 | 0224049a | Christos Stavrakakis | raise ValueError('Encryption key must be smaller than 32 bytes') |
17 | 0224049a | Christos Stavrakakis | if not len_secret in (16, 24, 32): |
18 | 30e0ed74 | Christos Stavrakakis | return secret + (blocksize - len(secret)) * padding |
19 | 30e0ed74 | Christos Stavrakakis | return secret
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20 | 30e0ed74 | Christos Stavrakakis | |
21 | 30e0ed74 | Christos Stavrakakis | |
22 | 3dbd9457 | Christos Stavrakakis | def encrypt(s, iv): |
23 | 3dbd9457 | Christos Stavrakakis | obj = AES.new(_pad_secret(SECRET_ENCRYPTION_KEY), AES.MODE_CFB, iv) |
24 | 30e0ed74 | Christos Stavrakakis | return obj.encrypt(s)
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25 | 30e0ed74 | Christos Stavrakakis | |
26 | 30e0ed74 | Christos Stavrakakis | |
27 | 3dbd9457 | Christos Stavrakakis | def decrypt(s, iv): |
28 | 3dbd9457 | Christos Stavrakakis | obj = AES.new(_pad_secret(SECRET_ENCRYPTION_KEY), AES.MODE_CFB, iv) |
29 | 30e0ed74 | Christos Stavrakakis | return obj.decrypt(s)
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30 | 30e0ed74 | Christos Stavrakakis | |
31 | 30e0ed74 | Christos Stavrakakis | |
32 | 30e0ed74 | Christos Stavrakakis | def encrypt_db_charfield(plaintext): |
33 | 68b952f9 | Christos Stavrakakis | if not plaintext: |
34 | 30e0ed74 | Christos Stavrakakis | return plaintext
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35 | 30e0ed74 | Christos Stavrakakis | salt = "".join([choice(letters + digits) for i in xrange(SALT_LEN)]) |
36 | 30e0ed74 | Christos Stavrakakis | |
37 | 3dbd9457 | Christos Stavrakakis | iv = Random.get_random_bytes(16)
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38 | 30e0ed74 | Christos Stavrakakis | plaintext = "%s%s" % (salt, plaintext)
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39 | 30e0ed74 | Christos Stavrakakis | # Encrypt and convert to binary
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40 | 3dbd9457 | Christos Stavrakakis | ciphertext = b2a_base64(encrypt(plaintext, iv)) |
41 | 3dbd9457 | Christos Stavrakakis | iv = b2a_base64(iv) |
42 | 30e0ed74 | Christos Stavrakakis | # Append prefix,salt and return encoded value
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43 | 3dbd9457 | Christos Stavrakakis | final = '%s:%s:%s$%s' % (DB_ENCRYPTED_FIELD_PREFIX, iv, salt, ciphertext)
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44 | 30e0ed74 | Christos Stavrakakis | return final.encode('utf8') |
45 | 30e0ed74 | Christos Stavrakakis | |
46 | 30e0ed74 | Christos Stavrakakis | |
47 | 30e0ed74 | Christos Stavrakakis | def decrypt_db_charfield(ciphertext): |
48 | 68b952f9 | Christos Stavrakakis | if not ciphertext: |
49 | 30e0ed74 | Christos Stavrakakis | return ciphertext
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50 | 30e0ed74 | Christos Stavrakakis | has_prefix = ciphertext.startswith(DB_ENCRYPTED_FIELD_PREFIX + ':')
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51 | 30e0ed74 | Christos Stavrakakis | if not has_prefix: # Non-encoded value |
52 | 30e0ed74 | Christos Stavrakakis | return ciphertext
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53 | 30e0ed74 | Christos Stavrakakis | else:
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54 | 3dbd9457 | Christos Stavrakakis | _, iv, ciphertext = ciphertext.split(':')
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55 | 30e0ed74 | Christos Stavrakakis | |
56 | 30e0ed74 | Christos Stavrakakis | pure_salt, encrypted = ciphertext.split('$')
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57 | 3dbd9457 | Christos Stavrakakis | iv = a2b_base64(iv) |
58 | 30e0ed74 | Christos Stavrakakis | |
59 | 3dbd9457 | Christos Stavrakakis | plaintext = decrypt(a2b_base64(encrypted), iv) |
60 | 30e0ed74 | Christos Stavrakakis | |
61 | 30e0ed74 | Christos Stavrakakis | salt = plaintext[:SALT_LEN] |
62 | 30e0ed74 | Christos Stavrakakis | plaintext = plaintext[SALT_LEN:] |
63 | 30e0ed74 | Christos Stavrakakis | |
64 | 30e0ed74 | Christos Stavrakakis | if salt != pure_salt:
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65 | 30e0ed74 | Christos Stavrakakis | # Can not decrtypt password
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66 | 30e0ed74 | Christos Stavrakakis | raise CorruptedPassword("Can not decrypt password. Check the key") |
67 | 30e0ed74 | Christos Stavrakakis | else:
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68 | 30e0ed74 | Christos Stavrakakis | return plaintext
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69 | 30e0ed74 | Christos Stavrakakis | |
70 | 30e0ed74 | Christos Stavrakakis | |
71 | 30e0ed74 | Christos Stavrakakis | class CorruptedPassword(Exception): |
72 | 30e0ed74 | Christos Stavrakakis | pass |