Commit c9f986d2 authored by Niels Möller's avatar Niels Möller

Extracted function _salsa20_core.

parent 3eff4cc8
2012-09-23 Niels Möller <nisse@lysator.liu.se>
* Makefile.in (nettle_SOURCES): Added salsa20-core-internal.c.
* salsa20-core-internal.c (_salsa20_core): New file and function,
extracted from salsa20_crypt.
* salsa20.h (_salsa20_core): Declare it.
* salsa20-crypt.c (salsa20_crypt): Use _salsa20_core.
2012-09-21 Niels Möller <nisse@lysator.liu.se>
* pbkdf2.c (pbkdf2): assert that iterations > 0. Reorganized
......
......@@ -82,6 +82,7 @@ nettle_SOURCES = aes-decrypt-internal.c aes-decrypt.c \
md2.c md2-meta.c md4.c md4-meta.c \
md5.c md5-compress.c md5-compat.c md5-meta.c \
ripemd160.c ripemd160-compress.c ripemd160-meta.c \
salsa20-core-internal.c \
salsa20-crypt.c salsa20-set-key.c \
sha1.c sha1-compress.c sha1-meta.c \
sha256.c sha256-compress.c sha224-meta.c sha256-meta.c \
......
/* salsa20-core-internal.c
*
* Internal interface to the Salsa20 core function.
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2012 Simon Josefsson, Niels Möller
*
* The nettle library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* The nettle library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the nettle library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02111-1301, USA.
*/
/* Based on:
salsa20-ref.c version 20051118
D. J. Bernstein
Public domain.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include <assert.h>
#include <string.h>
#include "salsa20.h"
#include "macros.h"
#ifdef WORDS_BIGENDIAN
#define LE_SWAP32(v) \
((ROTL32(8, v) & 0x00FF00FFUL) | \
(ROTL32(24, v) & 0xFF00FF00UL))
#else
#define LE_SWAP32(v) (v)
#endif
#define QROUND(x0, x1, x2, x3) do { \
x1 ^= ROTL32(7, x0 + x3); \
x2 ^= ROTL32(9, x1 + x0); \
x3 ^= ROTL32(13, x2 + x1); \
x0 ^= ROTL32(18, x3 + x2); \
} while(0)
void
_salsa20_core(uint32_t *dst, const uint32_t *src, unsigned rounds)
{
uint32_t x[_SALSA20_INPUT_LENGTH];
unsigned i;
assert ( (rounds & 1) == 0);
memcpy (x, src, sizeof(x));
for (i = 0; i < rounds;i += 2)
{
QROUND(x[0], x[4], x[8], x[12]);
QROUND(x[5], x[9], x[13], x[1]);
QROUND(x[10], x[14], x[2], x[6]);
QROUND(x[15], x[3], x[7], x[11]);
QROUND(x[0], x[1], x[2], x[3]);
QROUND(x[5], x[6], x[7], x[4]);
QROUND(x[10], x[11], x[8], x[9]);
QROUND(x[15], x[12], x[13], x[14]);
}
for (i = 0; i < _SALSA20_INPUT_LENGTH; i++)
{
uint32_t t = x[i] + src[i];
dst[i] = LE_SWAP32 (t);
}
}
......@@ -40,21 +40,6 @@
#include "macros.h"
#include "memxor.h"
#ifdef WORDS_BIGENDIAN
#define LE_SWAP32(v) \
((ROTL32(8, v) & 0x00FF00FFUL) | \
(ROTL32(24, v) & 0xFF00FF00UL))
#else
#define LE_SWAP32(v) (v)
#endif
#define QROUND(x0, x1, x2, x3) do { \
x1 ^= ROTL32(7, x0 + x3); \
x2 ^= ROTL32(9, x1 + x0); \
x3 ^= ROTL32(13, x2 + x1); \
x0 ^= ROTL32(18, x3 + x2); \
} while(0)
void
salsa20_crypt(struct salsa20_ctx *ctx,
unsigned length,
......@@ -67,26 +52,8 @@ salsa20_crypt(struct salsa20_ctx *ctx,
for (;;)
{
uint32_t x[_SALSA20_INPUT_LENGTH];
int i;
memcpy (x, ctx->input, sizeof(x));
for (i = 0;i < 10;i ++)
{
QROUND(x[0], x[4], x[8], x[12]);
QROUND(x[5], x[9], x[13], x[1]);
QROUND(x[10], x[14], x[2], x[6]);
QROUND(x[15], x[3], x[7], x[11]);
QROUND(x[0], x[1], x[2], x[3]);
QROUND(x[5], x[6], x[7], x[4]);
QROUND(x[10], x[11], x[8], x[9]);
QROUND(x[15], x[12], x[13], x[14]);
}
for (i = 0;i < _SALSA20_INPUT_LENGTH;++i)
{
uint32_t t = x[i] + ctx->input[i];
x[i] = LE_SWAP32 (t);
}
_salsa20_core (x, ctx->input, 20);
ctx->input[9] += (++ctx->input[8] == 0);
......
......@@ -37,6 +37,7 @@ extern "C" {
#define salsa20_set_key nettle_salsa20_set_key
#define salsa20_set_iv nettle_salsa20_set_iv
#define salsa20_crypt nettle_salsa20_crypt
#define _salsa20_core _nettle_salsa20_core
/* Minimum and maximum keysizes, and a reasonable default. In
* octets.*/
......@@ -75,6 +76,9 @@ salsa20_crypt(struct salsa20_ctx *ctx,
unsigned length, uint8_t *dst,
const uint8_t *src);
void
_salsa20_core(uint32_t *dst, const uint32_t *src, unsigned rounds);
#ifdef __cplusplus
}
#endif
......
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