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/* sha1.c
*
* The sha1 hash function.
* Defined by http://www.itl.nist.gov/fipspubs/fip180-1.htm.
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2001 Peter Gutmann, Andrew Kuchling, 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.
*/
/* Here's the first paragraph of Peter Gutmann's posting,
* <30ajo5$oe8@ccu2.auckland.ac.nz>:
*
* The following is my SHA (FIPS 180) code updated to allow use of the "fixed"
* SHA, thanks to Jim Gillogly and an anonymous contributor for the information on
* what's changed in the new version. The fix is a simple change which involves
* adding a single rotate in the initial expansion function. It is unknown
* whether this is an optimal solution to the problem which was discovered in the
* SHA or whether it's simply a bandaid which fixes the problem with a minimum of
* effort (for example the reengineering of a great many Capstone chips).
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "sha1.h"
#include "macros.h"
#include "nettle-write.h"
/* Initialize the SHA values */
void
sha1_init(struct sha1_ctx *ctx)
{
/* FIXME: Put the buffer last in the struct, and arrange so that we
can initialize with a single memcpy. */
static const uint32_t iv[_SHA1_DIGEST_LENGTH] =
{
/* SHA initial values */
0x67452301L,
0xEFCDAB89L,
0x98BADCFEL,
0x10325476L,
0xC3D2E1F0L,
};
memcpy(ctx->state, iv, sizeof(ctx->state));
ctx->count_low = ctx->count_high = 0;
/* Initialize buffer */
ctx->index = 0;
}
#define COMPRESS(ctx, data) (_nettle_sha1_compress((ctx)->state, data))
void
sha1_update(struct sha1_ctx *ctx,
unsigned length, const uint8_t *data)
{
MD_UPDATE (ctx, length, data, COMPRESS, MD_INCR(ctx));
}
void
sha1_digest(struct sha1_ctx *ctx,
unsigned length,
uint8_t *digest)
{
uint32_t high, low;
assert(length <= SHA1_DIGEST_SIZE);
MD_PAD(ctx, 8, COMPRESS);
/* There are 512 = 2^9 bits in one block */
high = (ctx->count_high << 9) | (ctx->count_low >> 23);
low = (ctx->count_low << 9) | (ctx->index << 3);
/* append the 64 bit count */
WRITE_UINT32(ctx->block + (SHA1_DATA_SIZE - 8), high);
WRITE_UINT32(ctx->block + (SHA1_DATA_SIZE - 4), low);
_nettle_sha1_compress(ctx->state, ctx->block);
_nettle_write_be32(length, digest, ctx->state);
sha1_init(ctx);
}
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