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/* sha3-permute.c
*
* The sha3 permutation function (aka Keccak).
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2012 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.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include "sha3.h"
#include "macros.h"
#define SHA3_ROUNDS 24
/* Based on the pseudocode description at
http://keccak.noekeon.org/specs_summary.html */
void
sha3_permute (struct sha3_state *state)
{
static const unsigned char rot[25] =
{
0, 1, 62, 28, 27,
36, 44, 6, 55, 20,
3, 10, 43, 25, 39,
41, 45, 15, 21, 8,
18, 2, 61, 56, 14,
};
static const unsigned char perm[25] =
{
0,10,20, 5,15,
16, 1,11,21, 6,
7,17, 2,12,22,
23, 8,18, 3,13,
14,24, 9,19, 4
};
static const uint64_t rc[SHA3_ROUNDS] = {
0x0000000000000001ULL, 0X0000000000008082ULL,
0X800000000000808AULL, 0X8000000080008000ULL,
0X000000000000808BULL, 0X0000000080000001ULL,
0X8000000080008081ULL, 0X8000000000008009ULL,
0X000000000000008AULL, 0X0000000000000088ULL,
0X0000000080008009ULL, 0X000000008000000AULL,
0X000000008000808BULL, 0X800000000000008BULL,
0X8000000000008089ULL, 0X8000000000008003ULL,
0X8000000000008002ULL, 0X8000000000000080ULL,
0X000000000000800AULL, 0X800000008000000AULL,
0X8000000080008081ULL, 0X8000000000008080ULL,
0X0000000080000001ULL, 0X8000000080008008ULL,
};
unsigned i;
#define A state->a
for (i = 0; i < SHA3_ROUNDS; i++)
{
uint64_t C[5], D[5], B[25];
unsigned x, y;
/* theta step */
C[0] = A[0] ^ A[5+0] ^ A[10+0] ^ A[15+0] ^ A[20+0];
C[1] = A[1] ^ A[5+1] ^ A[10+1] ^ A[15+1] ^ A[20+1];
C[2] = A[2] ^ A[5+2] ^ A[10+2] ^ A[15+2] ^ A[20+2];
C[3] = A[3] ^ A[5+3] ^ A[10+3] ^ A[15+3] ^ A[20+3];
C[4] = A[4] ^ A[5+4] ^ A[10+4] ^ A[15+4] ^ A[20+4];
D[0] = C[4] ^ ROTL64(1, C[1]);
D[1] = C[0] ^ ROTL64(1, C[2]);
D[2] = C[1] ^ ROTL64(1, C[3]);
D[3] = C[2] ^ ROTL64(1, C[4]);
D[4] = C[3] ^ ROTL64(1, C[0]);
for (x = 0; x < 5; x++)
for (y = 0; y < 25; y += 5)
A[y + x] ^= D[x];
/* rho and pi steps */
B[0] = A[0]; /* NOTE: ROTL64 doesn't work with shift count 0 */
for (x = 1; x < 25; x++)
B[perm[x]] = ROTL64 (rot[x], A[x]);
/* chi step */
for (y = 0; y < 25; y += 5)
{
A[y] = B[y] ^ (~B[y+1] & B[y+2]);
A[y+1] = B[y+1] ^ (~B[y+2] & B[y+3]);
A[y+2] = B[y+2] ^ (~B[y+3] & B[y+4]);
A[y+3] = B[y+3] ^ (~B[y+4] & B[y+0]);
A[y+4] = B[y+4] ^ (~B[y+0] & B[y+1]);
}
/* iota step */
A[0] ^= rc[i];
}
#undef A
}
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