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3a45f6ffe9
This is meant for use when encrypting the current time within the period in order to get a monotonically increasing revision counter without actually revealing our view of the time. This scheme is far from the most state-of-the-art: don't use it for anything else without careful analysis by somebody much smarter than I am. See ticket #25552 for some rationale for this logic.
40 lines
1.3 KiB
Python
40 lines
1.3 KiB
Python
#!/usr/bin/python3
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# Copyright 2018, The Tor Project, Inc. See LICENSE for licensing info.
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# Reference implementation for our rudimentary OPE code, used to
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# generate test vectors. See crypto_ope.c for more details.
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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
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from cryptography.hazmat.primitives.ciphers.algorithms import AES
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from cryptography.hazmat.backends import default_backend
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from binascii import a2b_hex
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#randomly generated and values.
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KEY = a2b_hex(
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"19e05891d55232c08c2cad91d612fdb9cbd6691949a0742434a76c80bc6992fe")
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PTS = [ 121132, 82283, 72661, 72941, 123122, 12154, 121574, 11391, 65845,
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86301, 61284, 70505, 30438, 60150, 114800, 109403, 21893, 123569,
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95617, 48561, 53334, 92746, 7110, 9612, 106958, 46889, 87790, 68878,
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47917, 121128, 108602, 28217, 69498, 63870, 57542, 122148, 46254,
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42850, 92661, 57720]
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IV = b'\x00' * 16
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backend = default_backend()
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def words():
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cipher = Cipher(algorithms.AES(KEY), modes.CTR(IV), backend=backend)
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e = cipher.encryptor()
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while True:
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v = e.update(b'\x00\x00')
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yield v[0] + 256 * v[1] + 1
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def encrypt(n):
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return sum(w for w, _ in zip(words(), range(n)))
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def example(n):
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return ' {{ {}, UINT64_C({}) }},'.format(n, encrypt(n))
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for v in PTS:
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print(example(v))
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