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74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
/* aes-set-key-internal.c
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Key setup for the aes/rijndael block cipher.
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Copyright (C) 2000, 2001, 2002 Rafael R. Sevilla, Niels Möller
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Copyright (C) 2013 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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/* Originally written by Rafael R. Sevilla <dido@pacific.net.ph> */
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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 "aes-internal.h"
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#include <assert.h>
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#include "macros.h"
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void
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_nettle_aes_set_key(unsigned nr, unsigned nk,
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uint32_t *subkeys, const uint8_t *key)
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{
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static const uint8_t rcon[10] = {
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0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80,0x1b,0x36,
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};
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const uint8_t *rp;
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unsigned lastkey, i;
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uint32_t t;
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assert(nk != 0);
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lastkey = (AES_BLOCK_SIZE/4) * (nr + 1);
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for (i=0, rp = rcon; i<nk; i++)
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subkeys[i] = LE_READ_UINT32(key + i*4);
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for (i=nk; i<lastkey; i++)
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{
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t = subkeys[i-1];
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if (i % nk == 0)
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t = SUBBYTE(ROTL32(24, t), aes_sbox) ^ *rp++;
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else if (nk > 6 && (i%nk) == 4)
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t = SUBBYTE(t, aes_sbox);
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subkeys[i] = subkeys[i-nk] ^ t;
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}
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}
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