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1.4.6
by Magnus Holmgren
Import upstream version 2.7 |
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/* salsa20r12-crypt.c
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*
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* The Salsa20 stream cipher.
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*/
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/* nettle, low-level cryptographics library
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*
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* Copyright (C) 2013 Nikos Mavrogiannopoulos
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*
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* The nettle library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or (at your
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* option) any later version.
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*
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* The nettle library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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* License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with the nettle library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02111-1301, USA.
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*/
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/* Based on:
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salsa20-ref.c version 20051118
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D. J. Bernstein
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Public domain.
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*/
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#if HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <string.h> |
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#include "salsa20.h" |
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#include "macros.h" |
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#include "memxor.h" |
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void
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salsa20r12_crypt(struct salsa20_ctx *ctx, |
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unsigned length, |
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uint8_t *c, |
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const uint8_t *m) |
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{
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uint32_t x[_SALSA20_INPUT_LENGTH]; |
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if (!length) |
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return; |
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for (;;) |
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{
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_salsa20_core (x, ctx->input, 12); |
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ctx->input[9] += (++ctx->input[8] == 0); |
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/* stopping at 2^70 length per nonce is user's responsibility */
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if (length <= SALSA20_BLOCK_SIZE) |
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{
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memxor3 (c, m, (uint8_t *) x, length); |
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return; |
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}
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memxor3 (c, m, (uint8_t *) x, SALSA20_BLOCK_SIZE); |
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length -= SALSA20_BLOCK_SIZE; |
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c += SALSA20_BLOCK_SIZE; |
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m += SALSA20_BLOCK_SIZE; |
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}
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}
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