65 lines
1.8 KiB
Python
65 lines
1.8 KiB
Python
#!/usr/bin/env python3
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# Copyright (c) 2016-2022 The Moneyrocket Core developers
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# Distributed under the MIT software license, see the accompanying
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# file COPYING or http://www.opensource.org/licenses/mit-license.php.
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"""SipHash-2-4 implementation.
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This implements SipHash-2-4. For convenience, an interface taking 256-bit
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integers is provided in addition to the one accepting generic data.
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"""
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def rotl64(n, b):
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return n >> (64 - b) | (n & ((1 << (64 - b)) - 1)) << b
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def siphash_round(v0, v1, v2, v3):
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v0 = (v0 + v1) & ((1 << 64) - 1)
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v1 = rotl64(v1, 13)
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v1 ^= v0
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v0 = rotl64(v0, 32)
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v2 = (v2 + v3) & ((1 << 64) - 1)
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v3 = rotl64(v3, 16)
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v3 ^= v2
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v0 = (v0 + v3) & ((1 << 64) - 1)
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v3 = rotl64(v3, 21)
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v3 ^= v0
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v2 = (v2 + v1) & ((1 << 64) - 1)
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v1 = rotl64(v1, 17)
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v1 ^= v2
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v2 = rotl64(v2, 32)
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return (v0, v1, v2, v3)
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def siphash(k0, k1, data):
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assert type(data) == bytes
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v0 = 0x736f6d6570736575 ^ k0
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v1 = 0x646f72616e646f6d ^ k1
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v2 = 0x6c7967656e657261 ^ k0
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v3 = 0x7465646279746573 ^ k1
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c = 0
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t = 0
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for d in data:
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t |= d << (8 * (c % 8))
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c = (c + 1) & 0xff
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if (c & 7) == 0:
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v3 ^= t
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v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
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v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
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v0 ^= t
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t = 0
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t = t | (c << 56)
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v3 ^= t
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v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
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v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
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v0 ^= t
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v2 ^= 0xff
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v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
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v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
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v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
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v0, v1, v2, v3 = siphash_round(v0, v1, v2, v3)
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return v0 ^ v1 ^ v2 ^ v3
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def siphash256(k0, k1, num):
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assert type(num) == int
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return siphash(k0, k1, num.to_bytes(32, 'little'))
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