You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
129 lines
3.0 KiB
C
129 lines
3.0 KiB
C
/* chacha-core-internal.c
|
|
|
|
Core functionality of the ChaCha stream cipher.
|
|
Heavily based on the Salsa20 implementation in Nettle.
|
|
|
|
Copyright (C) 2013 Joachim Strömbergson
|
|
Copyright (C) 2012 Simon Josefsson, Niels Möller
|
|
|
|
This file is part of GNU Nettle.
|
|
|
|
GNU Nettle is free software: you can redistribute it and/or
|
|
modify it under the terms of either:
|
|
|
|
* the GNU Lesser General Public License as published by the Free
|
|
Software Foundation; either version 3 of the License, or (at your
|
|
option) any later version.
|
|
|
|
or
|
|
|
|
* the GNU General Public License as published by the Free
|
|
Software Foundation; either version 2 of the License, or (at your
|
|
option) any later version.
|
|
|
|
or both in parallel, as here.
|
|
|
|
GNU Nettle is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
General Public License for more details.
|
|
|
|
You should have received copies of the GNU General Public License and
|
|
the GNU Lesser General Public License along with this program. If
|
|
not, see http://www.gnu.org/licenses/.
|
|
*/
|
|
|
|
/* Based on:
|
|
chacha-ref.c version 2008.01.20.
|
|
D. J. Bernstein
|
|
Public domain.
|
|
*/
|
|
|
|
#if HAVE_CONFIG_H
|
|
# include "config.h"
|
|
#endif
|
|
|
|
#include <assert.h>
|
|
#include <string.h>
|
|
|
|
#include "chacha.h"
|
|
#include "chacha-internal.h"
|
|
|
|
#include "bswap-internal.h"
|
|
#include "macros.h"
|
|
|
|
/* For fat builds */
|
|
#if HAVE_NATIVE_chacha_core
|
|
void
|
|
_nettle_chacha_core_c(uint32_t *dst, const uint32_t *src, unsigned rounds);
|
|
#define _nettle_chacha_core _nettle_chacha_core_c
|
|
#endif
|
|
|
|
#ifndef CHACHA_DEBUG
|
|
# define CHACHA_DEBUG 0
|
|
#endif
|
|
|
|
#if CHACHA_DEBUG
|
|
# include <stdio.h>
|
|
# define DEBUG(i) do { \
|
|
unsigned debug_j; \
|
|
for (debug_j = 0; debug_j < 16; debug_j++) \
|
|
{ \
|
|
if (debug_j == 0) \
|
|
fprintf(stderr, "%2d:", (i)); \
|
|
else if (debug_j % 4 == 0) \
|
|
fprintf(stderr, "\n "); \
|
|
fprintf(stderr, " %8x", x[debug_j]); \
|
|
} \
|
|
fprintf(stderr, "\n"); \
|
|
} while (0)
|
|
#else
|
|
# define DEBUG(i)
|
|
#endif
|
|
|
|
#define QROUND(x0, x1, x2, x3) do { \
|
|
x0 = x0 + x1; x3 = ROTL32(16, (x0 ^ x3)); \
|
|
x2 = x2 + x3; x1 = ROTL32(12, (x1 ^ x2)); \
|
|
x0 = x0 + x1; x3 = ROTL32(8, (x0 ^ x3)); \
|
|
x2 = x2 + x3; x1 = ROTL32(7, (x1 ^ x2)); \
|
|
} while(0)
|
|
|
|
void
|
|
_nettle_chacha_core(uint32_t *dst, const uint32_t *src, unsigned rounds)
|
|
{
|
|
uint32_t x[_CHACHA_STATE_LENGTH];
|
|
unsigned i;
|
|
|
|
assert ( (rounds & 1) == 0);
|
|
|
|
memcpy (x, src, sizeof(x));
|
|
for (i = 0; i < rounds;i += 2)
|
|
{
|
|
DEBUG (i);
|
|
QROUND(x[0], x[4], x[8], x[12]);
|
|
QROUND(x[1], x[5], x[9], x[13]);
|
|
QROUND(x[2], x[6], x[10], x[14]);
|
|
QROUND(x[3], x[7], x[11], x[15]);
|
|
|
|
DEBUG (i+1);
|
|
QROUND(x[0], x[5], x[10], x[15]);
|
|
QROUND(x[1], x[6], x[11], x[12]);
|
|
QROUND(x[2], x[7], x[8], x[13]);
|
|
QROUND(x[3], x[4], x[9], x[14]);
|
|
}
|
|
DEBUG (i);
|
|
|
|
for (i = 0; i < _CHACHA_STATE_LENGTH; i++)
|
|
{
|
|
uint32_t t = x[i] + src[i];
|
|
dst[i] = bswap32_if_be (t);
|
|
}
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|