mdw@git.distorted.org.uk Git - catacomb/blob - symm/rijndael-base.c

   1 /* -*-c-*-
   2  *
   3  * Low-level stuff for all Rijndael block sizes
   4  *
   5  * (c) 2001 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include "config.h"
  31
  32 #include <assert.h>
  33 #include <stdio.h>
  34
  35 #include <mLib/bits.h>
  36
  37 #include "blkc.h"
  38 #include "dispatch.h"
  39 #include "gcipher.h"
  40 #include "rijndael.h"
  41 #include "rijndael-base.h"
  42
  43 /*----- Global variables --------------------------------------------------*/
  44
  45 const octet rijndael_keysz[] = { KSZ_RANGE, RIJNDAEL_KEYSZ, 4, 32, 4 };
  46
  47 /*----- Main code ---------------------------------------------------------*/
  48
  49 /* --- @rijndael_setup@ --- *
  50  *
  51  * Arguments:   @rijndael_ctx *k@ = pointer to context to initialize
  52  *              @unsigned nb@ = number of words in the block
  53  *              @const void *buf@ = pointer to buffer of key material
  54  *              @size_t sz@ = size of the key material
  55  *
  56  * Returns:     ---
  57  *
  58  * Use:         Low-level key-scheduling.
  59  */
  60
  61 static void simple_setup(rijndael_ctx *k, unsigned nb,
  62                          const void *buf, unsigned nk)
  63 {
  64   unsigned nr = k->nr, nw;
  65   unsigned i, j, jj;
  66   const octet *p;
  67   uint32 ww;
  68
  69   /* --- Fetch the first key words out --- */
  70
  71   p = buf;
  72   for (i = 0; i < nk; i++) {
  73     k->w[i] = LOAD32_B(p);
  74     p += 4;
  75   }
  76
  77   /* --- Expand this material to fill the rest of the table --- */
  78
  79   nw = (nr + 1) * nb;
  80   ww = k->w[i - 1];
  81   p = RCON;
  82   for (; i < nw; i++) {
  83     uint32 w = k->w[i - nk];
  84     if (i % nk == 0) {
  85       ww = ROL32(ww, 8);
  86       w ^= SUB(S, ww, ww, ww, ww) ^ (*p++ << 24);
  87     } else if (nk > 6 && i % nk == 4)
  88       w ^= SUB(S, ww, ww, ww, ww);
  89     else
  90       w ^= ww;
  91     k->w[i] = ww = w;
  92   }
  93
  94   /* --- Make the decryption keys --- */
  95
  96   j = nw; i = 0;
  97
  98   j -= nb; jj = 0;
  99   for (; i < nb; i++)
 100     k->wi[i] = k->w[j + jj++];
 101
 102   for (; i < nw - nb; i += nb) {
 103     j -= nb;
 104     for (jj = 0; jj < nb; jj++) {
 105       uint32 w = k->w[j + jj];
 106       k->wi[i + jj] = MIX(U, w, w, w, w);
 107     }
 108   }
 109
 110   j -= nb; jj = 0;
 111   for (; i < nw; i++)
 112     k->wi[i] = k->w[j + jj++];
 113 }
 114
 115 CPU_DISPATCH(static, EMPTY, void, setup,
 116              (rijndael_ctx *k, unsigned nb, const void *buf, unsigned nk),
 117              (k, nb, buf, nk), pick_setup, simple_setup)
 118
 119 #if CPUFAM_X86 || CPUFAM_AMD64
 120 extern setup__functype rijndael_setup_x86ish_aesni;
 121 extern setup__functype rijndael_setup_x86ish_aesni_avx;
 122 #endif
 123 #if CPUFAM_ARMEL && HAVE_AS_ARMV8_CRYPTO
 124 extern setup__functype rijndael_setup_arm_crypto;
 125 #endif
 126 #if CPUFAM_ARM64
 127 extern setup__functype rijndael_setup_arm64_crypto;
 128 #endif
 129
 130 static setup__functype *pick_setup(void)
 131 {
 132 #if CPUFAM_X86 || CPUFAM_AMD64
 133   DISPATCH_PICK_COND(rijndael_setup, rijndael_setup_x86ish_aesni_avx,
 134                      cpu_feature_p(CPUFEAT_X86_AVX) &&
 135                      cpu_feature_p(CPUFEAT_X86_AESNI));
 136   DISPATCH_PICK_COND(rijndael_setup, rijndael_setup_x86ish_aesni,
 137                      cpu_feature_p(CPUFEAT_X86_AESNI));
 138 #endif
 139 #if CPUFAM_ARMEL && HAVE_AS_ARMV8_CRYPTO
 140   DISPATCH_PICK_COND(rijndael_setup, rijndael_setup_arm_crypto,
 141                      cpu_feature_p(CPUFEAT_ARM_AES));
 142 #endif
 143 #if CPUFAM_ARM64
 144   DISPATCH_PICK_COND(rijndael_setup, rijndael_setup_arm64_crypto,
 145                      cpu_feature_p(CPUFEAT_ARM_AES));
 146 #endif
 147   DISPATCH_PICK_FALLBACK(rijndael_setup, simple_setup);
 148 }
 149
 150 void rijndael_setup(rijndael_ctx *k, unsigned nb, const void *buf, size_t sz)
 151 {
 152   unsigned nk, nr;
 153
 154   /* --- Sort out the key size --- */
 155
 156   KSZ_ASSERT(rijndael, sz);
 157   nk = sz / 4;
 158
 159   /* --- Select the number of rounds --- */
 160
 161   nr = (nk > nb ? nk : nb) + 6;
 162   if (nr < 10)
 163     nr = 10;
 164   k->nr = nr;
 165
 166   /* --- Do the main setup --- */
 167
 168   setup(k, nb, buf, nk);
 169 }
 170
 171 /*----- That's all, folks -------------------------------------------------*/