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author | Niels Möller <nisse@lysator.liu.se> | 2014-01-27 13:42:42 +0100 |
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committer | Niels Möller <nisse@lysator.liu.se> | 2014-01-27 13:42:42 +0100 |
commit | 93fc1d1460fdba49c100f880dfab16aa6402d552 (patch) | |
tree | 5db9d1695580015bd3aa8a2e7571e118925b5118 /chacha128-set-key.c | |
parent | e57d2fe2e0385f219e1e4f7adc051ad6b98905c1 (diff) | |
download | nettle-93fc1d1460fdba49c100f880dfab16aa6402d552.tar.gz |
Implemented chacha, based on contribution by Joachim Strömbergson.
Diffstat (limited to 'chacha128-set-key.c')
-rw-r--r-- | chacha128-set-key.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/chacha128-set-key.c b/chacha128-set-key.c new file mode 100644 index 00000000..569e801c --- /dev/null +++ b/chacha128-set-key.c @@ -0,0 +1,61 @@ +/* chacha128-set-key.c + * + * ChaCha key setup for 128-bit keys. + * Based on the Salsa20 implementation in Nettle. + */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2013 Joachim Strömbergon + * Copyright (C) 2012 Simon Josefsson + * Copyright (C) 2012, 2014 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: + ChaCha specification (doc id: 4027b5256e17b9796842e6d0f68b0b5e) and reference + implementation dated 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 "macros.h" + +void +chacha128_set_key(struct chacha_ctx *ctx, const uint8_t *key) +{ + static const uint32_t tau[4] = { + /* "expand 16-byte k" */ + 0x61707865, 0x3120646e, 0x79622d36, 0x6b206574 + }; + + ctx->state[8] = ctx->state[4] = LE_READ_UINT32(key + 0); + ctx->state[9] = ctx->state[5] = LE_READ_UINT32(key + 4); + ctx->state[10] = ctx->state[6] = LE_READ_UINT32(key + 8); + ctx->state[11] = ctx->state[7] = LE_READ_UINT32(key + 12); + + memcpy (ctx->state, tau, sizeof(tau)); +} |