cryptol/examples/FNV-a1.cry
2016-01-19 18:19:35 -08:00

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/*
* Copyright (c) 2014-2016 Galois, Inc.
* Distributed under the terms of the BSD3 license (see LICENSE file)
*/
fnv1a : {n} (fin n) => [n] -> [64]
fnv1a ws = fnv1a' (pad ws)
pad : {msgLen,chunks,padding}
( fin msgLen
, chunks == (msgLen+7) / 8
, padding == (8 - msgLen % 8) % 8
)
=> [msgLen] -> [chunks][8]
pad msg = split (msg # (zero:[padding]))
fnv1a' : {chunks} (fin chunks) => [chunks][8] -> [64]
fnv1a' msg = Ss ! 0
where
Ss = [fnv1a_offset_basis] #
[ block s m
| s <- Ss
| m <- msg
]
block : {padding} ( padding == 64 - 8) => [64] -> [8] -> [64]
block state val = (state ^ ((zero : [padding]) # val)) * fnv1a_prime
fnv1a_offset_basis : [64]
fnv1a_offset_basis = 14695981039346656037
fnv1a_prime : [64]
fnv1a_prime = 1099511628211
t1 = fnv1a [] == 0xcbf29ce484222325
t2 = fnv1a (join "a") == 0xaf63dc4c8601ec8c
t3 = fnv1a (join "foobar") == 0x85944171f73967e8
property testsPass = [t1, t2, t3] == ~zero