97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
/* chacha.h
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The ChaCha stream cipher.
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Copyright (C) 2013 Joachim Strömbergson
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Copyright (C) 2012 Simon Josefsson
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Copyright (C) 2014 Niels Möller
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This file is part of GNU Nettle.
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GNU Nettle is free software: you can redistribute it and/or
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modify it under the terms of either:
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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or both in parallel, as here.
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GNU Nettle is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see http://www.gnu.org/licenses/.
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*/
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#ifndef NETTLE_CHACHA_H_INCLUDED
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#define NETTLE_CHACHA_H_INCLUDED
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#include "nettle-types.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Name mangling */
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#define chacha_set_key nettle_chacha_set_key
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#define chacha_set_nonce nettle_chacha_set_nonce
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#define chacha_set_nonce96 nettle_chacha_set_nonce96
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#define chacha_crypt nettle_chacha_crypt
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#define _chacha_core _nettle_chacha_core
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/* Currently, only 256-bit keys are supported. */
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#define CHACHA_KEY_SIZE 32
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#define CHACHA_BLOCK_SIZE 64
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#define CHACHA_NONCE_SIZE 8
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#define CHACHA_NONCE96_SIZE 12
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#define _CHACHA_STATE_LENGTH 16
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struct chacha_ctx
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{
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/* Indices 0-3 holds a constant (SIGMA or TAU).
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Indices 4-11 holds the key.
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Indices 12-13 holds the block counter.
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Indices 14-15 holds the IV:
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This creates the state matrix:
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C C C C
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K K K K
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K K K K
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B B I I
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*/
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uint32_t state[_CHACHA_STATE_LENGTH];
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};
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void
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chacha_set_key(struct chacha_ctx *ctx, const uint8_t *key);
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void
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chacha_set_nonce(struct chacha_ctx *ctx, const uint8_t *nonce);
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void
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chacha_set_nonce96(struct chacha_ctx *ctx, const uint8_t *nonce);
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void
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chacha_crypt(struct chacha_ctx *ctx, size_t length,
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uint8_t *dst, const uint8_t *src);
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void
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_chacha_core(uint32_t *dst, const uint32_t *src, unsigned rounds);
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#ifdef __cplusplus
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}
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#endif
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#endif /* NETTLE_CHACHA_H_INCLUDED */
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