1
/* salsa20-core-internal.c
3
* Internal interface to the Salsa20 core function.
6
/* nettle, low-level cryptographics library
8
* Copyright (C) 2012 Simon Josefsson, Niels Möller
10
* The nettle library is free software; you can redistribute it and/or modify
11
* it under the terms of the GNU Lesser General Public License as published by
12
* the Free Software Foundation; either version 2.1 of the License, or (at your
13
* option) any later version.
15
* The nettle library is distributed in the hope that it will be useful, but
16
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
17
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
18
* License for more details.
20
* You should have received a copy of the GNU Lesser General Public License
21
* along with the nettle library; see the file COPYING.LIB. If not, write to
22
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
27
salsa20-ref.c version 20051118
43
#ifdef WORDS_BIGENDIAN
44
#define LE_SWAP32(v) \
45
((ROTL32(8, v) & 0x00FF00FFUL) | \
46
(ROTL32(24, v) & 0xFF00FF00UL))
48
#define LE_SWAP32(v) (v)
51
#define QROUND(x0, x1, x2, x3) do { \
52
x1 ^= ROTL32(7, x0 + x3); \
53
x2 ^= ROTL32(9, x1 + x0); \
54
x3 ^= ROTL32(13, x2 + x1); \
55
x0 ^= ROTL32(18, x3 + x2); \
59
_salsa20_core(uint32_t *dst, const uint32_t *src, unsigned rounds)
61
uint32_t x[_SALSA20_INPUT_LENGTH];
64
assert ( (rounds & 1) == 0);
66
memcpy (x, src, sizeof(x));
67
for (i = 0; i < rounds;i += 2)
69
QROUND(x[0], x[4], x[8], x[12]);
70
QROUND(x[5], x[9], x[13], x[1]);
71
QROUND(x[10], x[14], x[2], x[6]);
72
QROUND(x[15], x[3], x[7], x[11]);
74
QROUND(x[0], x[1], x[2], x[3]);
75
QROUND(x[5], x[6], x[7], x[4]);
76
QROUND(x[10], x[11], x[8], x[9]);
77
QROUND(x[15], x[12], x[13], x[14]);
80
for (i = 0; i < _SALSA20_INPUT_LENGTH; i++)
82
uint32_t t = x[i] + src[i];
83
dst[i] = LE_SWAP32 (t);
added
removed
salsa20-core-internal.c
