cryptol/examples/Salsa20.cry
2014-09-10 14:27:08 -07:00

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/*
* Copyright (c) 2013-2014 Galois, Inc.
* Distributed under the terms of the BSD3 license (see LICENSE file)
*/
// see http://cr.yp.to/snuffle/spec.pdf
module Salsa20 where
quarterround : [4][32] -> [4][32]
quarterround [y0, y1, y2, y3] = [z0, z1, z2, z3]
where
z1 = y1 ^ ((y0 + y3) <<< 0x7)
z2 = y2 ^ ((z1 + y0) <<< 0x9)
z3 = y3 ^ ((z2 + z1) <<< 0xd)
z0 = y0 ^ ((z3 + z2) <<< 0x12)
quarterround_passes_tests =
(quarterround [0x00000000, 0x00000000, 0x00000000, 0x00000000] == [0x00000000, 0x00000000, 0x00000000, 0x00000000]) &&
(quarterround [0x00000001, 0x00000000, 0x00000000, 0x00000000] == [0x08008145, 0x00000080, 0x00010200, 0x20500000]) &&
(quarterround [0x00000000, 0x00000001, 0x00000000, 0x00000000] == [0x88000100, 0x00000001, 0x00000200, 0x00402000]) &&
(quarterround [0x00000000, 0x00000000, 0x00000001, 0x00000000] == [0x80040000, 0x00000000, 0x00000001, 0x00002000]) &&
(quarterround [0x00000000, 0x00000000, 0x00000000, 0x00000001] == [0x00048044, 0x00000080, 0x00010000, 0x20100001]) &&
(quarterround [0xe7e8c006, 0xc4f9417d, 0x6479b4b2, 0x68c67137] == [0xe876d72b, 0x9361dfd5, 0xf1460244, 0x948541a3]) &&
(quarterround [0xd3917c5b, 0x55f1c407, 0x52a58a7a, 0x8f887a3b] == [0x3e2f308c, 0xd90a8f36, 0x6ab2a923, 0x2883524c])
// rowround : [16][32] -> [16][32]
rowround [y0, y1, y2, y3, y4, y5, y6, y7, y8, y9, y10, y11, y12, y13, y14, y15] =
[z0, z1, z2, z3, z4, z5, z6, z7, z8, z9, z10, z11, z12, z13, z14, z15]
where
[ z0, z1, z2, z3] = quarterround [ y0, y1, y2, y3]
[ z5, z6, z7, z4] = quarterround [ y5, y6, y7, y4]
[z10, z11, z8, z9] = quarterround [y10, y11, y8, y9]
[z15, z12, z13, z14] = quarterround [y15, y12, y13, y14]
rowround_passes_tests =
(rowround [0x00000001, 0x00000000, 0x00000000, 0x00000000,
0x00000001, 0x00000000, 0x00000000, 0x00000000,
0x00000001, 0x00000000, 0x00000000, 0x00000000,
0x00000001, 0x00000000, 0x00000000, 0x00000000] ==
[0x08008145, 0x00000080, 0x00010200, 0x20500000,
0x20100001, 0x00048044, 0x00000080, 0x00010000,
0x00000001, 0x00002000, 0x80040000, 0x00000000,
0x00000001, 0x00000200, 0x00402000, 0x88000100]) &&
(rowround [0x08521bd6, 0x1fe88837, 0xbb2aa576, 0x3aa26365,
0xc54c6a5b, 0x2fc74c2f, 0x6dd39cc3, 0xda0a64f6,
0x90a2f23d, 0x067f95a6, 0x06b35f61, 0x41e4732e,
0xe859c100, 0xea4d84b7, 0x0f619bff, 0xbc6e965a] ==
[0xa890d39d, 0x65d71596, 0xe9487daa, 0xc8ca6a86,
0x949d2192, 0x764b7754, 0xe408d9b9, 0x7a41b4d1,
0x3402e183, 0x3c3af432, 0x50669f96, 0xd89ef0a8,
0x0040ede5, 0xb545fbce, 0xd257ed4f, 0x1818882d])
/* commented out for now -- not called, and type checker not yet happy
rowround_opt : [16][32] -> [16][32]
rowround_opt ys = join [ (quarterround (yi>>>i))<<<i | yi <- split ys | i <- [0 .. 0x3] ]
rowround_opt_is_rowround ys = rowround ys == rowround_opt ys
*/
columnround : [16][32] -> [16][32]
columnround [x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15] =
[y0, y1, y2, y3, y4, y5, y6, y7, y8, y9, y10, y11, y12, y13, y14, y15]
where
[ y0, y4, y8, y12] = quarterround [ x0, x4, x8, x12]
[ y5, y9, y13, y1] = quarterround [ x5, x9, x13, x1]
[y10, y14, y2, y6] = quarterround [x10, x14, x2, x6]
[y15, y3, y7, y11] = quarterround [x15, x3, x7, x11]
columnround_passes_tests =
(columnround [0x00000001, 0x00000000, 0x00000000, 0x00000000,
0x00000001, 0x00000000, 0x00000000, 0x00000000,
0x00000001, 0x00000000, 0x00000000, 0x00000000,
0x00000001, 0x00000000, 0x00000000, 0x00000000] ==
[0x10090288, 0x00000000, 0x00000000, 0x00000000,
0x00000101, 0x00000000, 0x00000000, 0x00000000,
0x00020401, 0x00000000, 0x00000000, 0x00000000,
0x40a04001, 0x00000000, 0x00000000, 0x00000000]) &&
(columnround [0x08521bd6, 0x1fe88837, 0xbb2aa576, 0x3aa26365,
0xc54c6a5b, 0x2fc74c2f, 0x6dd39cc3, 0xda0a64f6,
0x90a2f23d, 0x067f95a6, 0x06b35f61, 0x41e4732e,
0xe859c100, 0xea4d84b7, 0x0f619bff, 0xbc6e965a] ==
[0x8c9d190a, 0xce8e4c90, 0x1ef8e9d3, 0x1326a71a,
0x90a20123, 0xead3c4f3, 0x63a091a0, 0xf0708d69,
0x789b010c, 0xd195a681, 0xeb7d5504, 0xa774135c,
0x481c2027, 0x53a8e4b5, 0x4c1f89c5, 0x3f78c9c8])
/* commented out for now -- not called, and type checker not yet happy
columnround_opt : [16][32] -> [16][32]
columnround_opt xs = join (transpose [ (quarterround (xi<<<i))>>>i | xi <- transpose(split xs) | i <- [0 .. 3] ])
columnround_opt_is_columnround xs = columnround xs == columnround_opt xs
*/
property columnround_is_transpose_of_rowround ys =
rowround ys == join(transpose(split(columnround(xs))))
where xs = join(transpose(split(ys)))
doubleround : [16][32] -> [16][32]
doubleround(xs) = rowround(columnround(xs))
doubleround_passes_tests =
(doubleround [0x00000001, 0x00000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000] ==
[0x8186a22d, 0x0040a284, 0x82479210, 0x06929051,
0x08000090, 0x02402200, 0x00004000, 0x00800000,
0x00010200, 0x20400000, 0x08008104, 0x00000000,
0x20500000, 0xa0000040, 0x0008180a, 0x612a8020]) &&
(doubleround [0xde501066, 0x6f9eb8f7, 0xe4fbbd9b, 0x454e3f57,
0xb75540d3, 0x43e93a4c, 0x3a6f2aa0, 0x726d6b36,
0x9243f484, 0x9145d1e8, 0x4fa9d247, 0xdc8dee11,
0x054bf545, 0x254dd653, 0xd9421b6d, 0x67b276c1] ==
[0xccaaf672, 0x23d960f7, 0x9153e63a, 0xcd9a60d0,
0x50440492, 0xf07cad19, 0xae344aa0, 0xdf4cfdfc,
0xca531c29, 0x8e7943db, 0xac1680cd, 0xd503ca00,
0xa74b2ad6, 0xbc331c5c, 0x1dda24c7, 0xee928277])
// byteify : {n}(fin n) => [n][32] -> [n][8] // ideal
byteify : [32] -> [4][8] // help the type checker along
byteify xs = groupBy`{8}xs
wordendianswap : [4][8] -> [4][8]
wordendianswap b = reverse b
littleendian : [4][8] -> [32]
littleendian b = join(reverse b)
littleendian_passes_tests =
(littleendian [ 0, 0, 0, 0] == 0x00000000) &&
(littleendian [ 86, 75, 30, 9] == 0x091e4b56) &&
(littleendian [255, 255, 255, 250] == 0xfaffffff)
littleendian_inverse : [32] -> [4][8]
littleendian_inverse b = reverse(split b)
littleendian_is_invertable b = littleendian_inverse(littleendian(b)) == b
Salsa20 : [64][8] -> [64][8]
Salsa20 xs = join(ar)
where
ar = [ wordendianswap (byteify words) | words <- xw + (zs@0xa) ]
xw = [ littleendian(xi) | xi <- split xs ]
zs = [xw] # [ doubleround(zi) | zi <- zs ]
Salsa20_passes_tests =
(Salsa20 [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] ==
[ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]) &&
(Salsa20 [211, 159, 13, 115, 76, 55, 82, 183, 3, 117, 222, 37, 191, 187, 234, 136,
49, 237, 179, 48, 1, 106, 178, 219, 175, 199, 166, 48, 86, 16, 179, 207,
31, 240, 32, 63, 15, 83, 93, 161, 116, 147, 48, 113, 238, 55, 204, 36,
79, 201, 235, 79, 3, 81, 156, 47, 203, 26, 244, 243, 88, 118, 104, 54] ==
[109, 42, 178, 168, 156, 240, 248, 238, 168, 196, 190, 203, 26, 110, 170, 154,
29, 29, 150, 26, 150, 30, 235, 249, 190, 163, 251, 48, 69, 144, 51, 57,
118, 40, 152, 157, 180, 57, 27, 94, 107, 42, 236, 35, 27, 111, 114, 114,
219, 236, 232, 135, 111, 155, 110, 18, 24, 232, 95, 158, 179, 19, 48, 202]) &&
(Salsa20 [ 88, 118, 104, 54, 79, 201, 235, 79, 3, 81, 156, 47, 203, 26, 244, 243,
191, 187, 234, 136, 211, 159, 13, 115, 76, 55, 82, 183, 3, 117, 222, 37,
86, 16, 179, 207, 49, 237, 179, 48, 1, 106, 178, 219, 175, 199, 166, 48,
238, 55, 204, 36, 31, 240, 32, 63, 15, 83, 93, 161, 116, 147, 48, 113] ==
[179, 19, 48, 202, 219, 236, 232, 135, 111, 155, 110, 18, 24, 232, 95, 158,
26, 110, 170, 154, 109, 42, 178, 168, 156, 240, 248, 238, 168, 196, 190, 203,
69, 144, 51, 57, 29, 29, 150, 26, 150, 30, 235, 249, 190, 163, 251, 48,
27, 111, 114, 114, 118, 40, 152, 157, 180, 57, 27, 94, 107, 42, 236, 35])
property Salsa20_has_no_collisions x1 x2 =
if(x1 != x2) then doubleround(x1) != doubleround(x2) else True
// Salsa 20 supports two key sizes, [16][8] and [32][8]
Salsa20_expansion : {a} (a >= 1, 2 >= a) => ([16*a][8], [16][8]) -> [64][8]
Salsa20_expansion(k, n) = z
where
[s0, s1, s2, s3] = split("expand 32-byte k") : [4][4][8]
[t0, t1, t2, t3] = split("expand 16-byte k") : [4][4][8]
x = if(`a == 2) then s0 # k0 # s1 # n # s2 # k1 # s3
else t0 # k0 # t1 # n # t2 # k0 # t3
z = Salsa20(x)
[k0, k1] = (split(k#zero)):[2][16][8]
Salsa20_encrypt : {a, b} (a >= 1, 2 >= a, fin b) => ([16*a][8], [8][8], [b][8]) -> [b][8]
Salsa20_encrypt(k, v, m) = c
where
salsa = take`{b} (join [ Salsa20_expansion(k, v#(split i)) | i <- [0, 1 ... ] ])
c = m ^ salsa