sha3.c

   1 /* sha3.c
   2
   3    The sha3 hash function.
   4
   5    Copyright (C) 2012 Niels Möller
   6
   7    This file is part of GNU Nettle.
   8
   9    GNU Nettle is free software: you can redistribute it and/or
  10    modify it under the terms of either:
  11
  12      * the GNU Lesser General Public License as published by the Free
  13        Software Foundation; either version 3 of the License, or (at your
  14        option) any later version.
  15
  16    or
  17
  18      * the GNU General Public License as published by the Free
  19        Software Foundation; either version 2 of the License, or (at your
  20        option) any later version.
  21
  22    or both in parallel, as here.
  23
  24    GNU Nettle is distributed in the hope that it will be useful,
  25    but WITHOUT ANY WARRANTY; without even the implied warranty of
  26    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  27    General Public License for more details.
  28
  29    You should have received copies of the GNU General Public License and
  30    the GNU Lesser General Public License along with this program.  If
  31    not, see http://www.gnu.org/licenses/.
  32 */
  33
  34 #if HAVE_CONFIG_H
  35 # include "config.h"
  36 #endif
  37
  38 #include <assert.h>
  39 #include <string.h>
  40
  41 #include "sha3.h"
  42 #include "sha3-internal.h"
  43
  44 #include "macros.h"
  45 #include "md-internal.h"
  46 #include "memxor.h"
  47
  48 #if WORDS_BIGENDIAN
  49 static void
  50 sha3_xor_block (struct sha3_state *state, unsigned length, const uint8_t *data)
  51 {
  52   assert ( (length & 7) == 0);
  53   {
  54     uint64_t *p;
  55     for (p = state->a; length > 0; p++, length -= 8, data += 8)
  56       *p ^= LE_READ_UINT64 (data);
  57   }
  58 }
  59 #else /* !WORDS_BIGENDIAN */
  60 #define sha3_xor_block(state, length, data) memxor (state->a, data, length)
  61 #endif
  62
  63 static void
  64 sha3_absorb (struct sha3_state *state, unsigned length, const uint8_t *data)
  65 {
  66   sha3_xor_block (state, length, data);
  67   sha3_permute (state);
  68 }
  69
  70 unsigned
  71 _nettle_sha3_update (struct sha3_state *state,
  72                      unsigned block_size, uint8_t *block,
  73                      unsigned pos,
  74                      size_t length, const uint8_t *data)
  75 {
  76   assert (pos < block_size);
  77
  78   if (!length)
  79     return pos;
  80
  81   if (pos > 0)
  82     {
  83       MD_FILL_OR_RETURN_INDEX (block_size, block, pos, length, data);
  84       sha3_absorb (state, block_size, block);
  85     }
  86   for (; length >= block_size; length -= block_size, data += block_size)
  87     sha3_absorb (state, block_size, data);
  88
  89   memcpy (block, data, length);
  90   return length;
  91 }
  92
  93 void
  94 _nettle_sha3_pad (struct sha3_state *state,
  95                   unsigned block_size, uint8_t *block, unsigned pos, uint8_t magic)
  96 {
  97   assert (pos < block_size);
  98   block[pos++] = magic;
  99
 100   memset (block + pos, 0, block_size - pos);
 101   block[block_size - 1] |= 0x80;
 102
 103   sha3_xor_block (state, block_size, block);
 104 }