├── README.md
└── ore.py


/README.md:
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1 | This is a simple implementation in Python of the Order Revealing scheme of Chenette et al. For more details refer to the original work:
2 | 
3 | Chenette, N., Lewi, K., Weis, S. A., & Wu, D. J. (2016). Practical order-revealing encryption with limited leakage. In Proceedings of the 23rd International Conference on Fast Software Encryption (IACR-FSE).
4 | 


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/ore.py:
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 1 | import hashlib
 2 | import random
 3 | from string import ascii_uppercase, digits
 4 | LEN = 16
 5 | 
 6 | 
 7 | def rnd_word(n):
 8 |     return ''.join(random.choice(ascii_uppercase + digits) for _ in range(n))
 9 | 
10 | 
11 | def prf(msg, k):
12 |     pad = "0" * (LEN - len(msg))
13 |     return int(hashlib.sha224(str(msg) + pad + str(k)).hexdigest(), 16)
14 | 
15 | 
16 | def ore_enc(m, k):
17 |     tmp_m = ""
18 |     tmpres = ""
19 |     for i in m:
20 |         tmp_m += i
21 |         tmpres += str((prf(tmp_m[:-1], k) + int(tmp_m[-1])) % 3)
22 |     return tmpres
23 | 
24 | 
25 | def ore_comp(u, v):
26 |     if u == v:
27 |         return 0
28 |     L = len(u)
29 |     cnt = 0
30 |     while u[cnt] == v[cnt]:
31 |         cnt += 1
32 |     if (int(u[cnt]) + 1) % 3 == int(v[cnt]):
33 |         return -1
34 |     else:
35 |         return 1
36 | 
37 | 
38 | def int_comp(u, v):
39 |     if u == v:
40 |         return 0
41 |     elif u > v:
42 |         return 1
43 |     else:
44 |         return -1
45 | 
46 | cnt = 0
47 | tests = 100
48 | for i in range(tests):
49 |     passwd = rnd_word(10)
50 |     num1 = random.randrange(2**63, 2**64)
51 |     num2 = random.randrange(2**63, 2**64)
52 | 
53 |     a = ore_enc(bin(num1)[2:], passwd)
54 |     b = ore_enc(bin(num2)[2:], passwd)
55 |     if ore_comp(a, b) == int_comp(num1, num2):
56 |         cnt += 1
57 | print "Succeded in: %d out of %d tests." % (cnt, tests)
58 | 


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