From 93fc1d1460fdba49c100f880dfab16aa6402d552 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Niels=20M=C3=B6ller?= Date: Mon, 27 Jan 2014 13:42:42 +0100 Subject: =?UTF-8?q?Implemented=20chacha,=20based=20on=20contribution=20by?= =?UTF-8?q?=20Joachim=20Str=C3=B6mbergson.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- chacha128-set-key.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 chacha128-set-key.c (limited to 'chacha128-set-key.c') 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 +#include + +#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)); +} -- cgit v1.2.1