| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: rijndael-base.c,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
| 4 | * |
| 5 | * Low-level stuff for all Rijndael block sizes |
| 6 | * |
| 7 | * (c) 2001 Straylight/Edgeware |
| 8 | */ |
| 9 | |
| 10 | /*----- Licensing notice --------------------------------------------------* |
| 11 | * |
| 12 | * This file is part of Catacomb. |
| 13 | * |
| 14 | * Catacomb is free software; you can redistribute it and/or modify |
| 15 | * it under the terms of the GNU Library General Public License as |
| 16 | * published by the Free Software Foundation; either version 2 of the |
| 17 | * License, or (at your option) any later version. |
| 18 | * |
| 19 | * Catacomb is distributed in the hope that it will be useful, |
| 20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 22 | * GNU Library General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU Library General Public |
| 25 | * License along with Catacomb; if not, write to the Free |
| 26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 27 | * MA 02111-1307, USA. |
| 28 | */ |
| 29 | |
| 30 | /*----- Header files ------------------------------------------------------*/ |
| 31 | |
| 32 | #include <assert.h> |
| 33 | #include <stdio.h> |
| 34 | |
| 35 | #include <mLib/bits.h> |
| 36 | |
| 37 | #include "blkc.h" |
| 38 | #include "gcipher.h" |
| 39 | #include "rijndael.h" |
| 40 | #include "rijndael-base.h" |
| 41 | #include "rijndael-tab.h" |
| 42 | |
| 43 | /*----- Global variables --------------------------------------------------*/ |
| 44 | |
| 45 | const octet rijndael_keysz[] = { KSZ_RANGE, RIJNDAEL_KEYSZ, 4, 32, 4 }; |
| 46 | |
| 47 | /*----- Constant tables ---------------------------------------------------*/ |
| 48 | |
| 49 | const octet rijndael_s[256] = RIJNDAEL_S; |
| 50 | const octet rijndael_si[256] = RIJNDAEL_SI; |
| 51 | const uint32 rijndael_t[4][256] = RIJNDAEL_T; |
| 52 | const uint32 rijndael_ti[4][256] = RIJNDAEL_TI; |
| 53 | const uint32 rijndael_u[4][256] = RIJNDAEL_U; |
| 54 | const octet rijndael_rcon[] = RIJNDAEL_RCON; |
| 55 | |
| 56 | /*----- Main code ---------------------------------------------------------*/ |
| 57 | |
| 58 | /* --- @rijndael_setup@ --- * |
| 59 | * |
| 60 | * Arguments: @rijndael_ctx *k@ = pointer to context to initialize |
| 61 | * @unsigned nb@ = number of words in the block |
| 62 | * @const void *buf@ = pointer to buffer of key material |
| 63 | * @size_t sz@ = size of the key material |
| 64 | * |
| 65 | * Returns: --- |
| 66 | * |
| 67 | * Use: Low-level key-scheduling. |
| 68 | */ |
| 69 | |
| 70 | void rijndael_setup(rijndael_ctx *k, unsigned nb, const void *buf, size_t sz) |
| 71 | { |
| 72 | unsigned nk, nr, nw; |
| 73 | unsigned i, j, jj; |
| 74 | const octet *p; |
| 75 | uint32 ww; |
| 76 | |
| 77 | /* --- Sort out the key size --- */ |
| 78 | |
| 79 | KSZ_ASSERT(rijndael, sz); |
| 80 | nk = sz / 4; |
| 81 | |
| 82 | /* --- Select the number of rounds --- */ |
| 83 | |
| 84 | nr = (nk > nb ? nk : nb) + 6; |
| 85 | if (nr < 10) |
| 86 | nr = 10; |
| 87 | k->nr = nr; |
| 88 | |
| 89 | /* --- Fetch the first key words out --- */ |
| 90 | |
| 91 | p = buf; |
| 92 | for (i = 0; i < nk; i++) { |
| 93 | k->w[i] = LOAD32_L(p); |
| 94 | p += 4; |
| 95 | } |
| 96 | |
| 97 | /* --- Expand this material to fill the rest of the table --- */ |
| 98 | |
| 99 | nw = (nr + 1) * nb; |
| 100 | ww = k->w[i - 1]; |
| 101 | p = RCON; |
| 102 | for (; i < nw; i++) { |
| 103 | uint32 w = k->w[i - nk]; |
| 104 | if (i % nk == 0) { |
| 105 | ww = ROR32(ww, 8); |
| 106 | w ^= SUB(S, ww, ww, ww, ww) ^ *p++; |
| 107 | } else if (nk > 6 && i % nk == 4) |
| 108 | w ^= SUB(S, ww, ww, ww, ww); |
| 109 | else |
| 110 | w ^= ww; |
| 111 | k->w[i] = ww = w; |
| 112 | } |
| 113 | |
| 114 | /* --- Make the decryption keys --- */ |
| 115 | |
| 116 | j = nw; i = 0; |
| 117 | |
| 118 | j -= nb; jj = 0; |
| 119 | for (; i < nb; i++) |
| 120 | k->wi[i] = k->w[j + jj++]; |
| 121 | |
| 122 | for (; i < nw - nb; i += nb) { |
| 123 | j -= nb; |
| 124 | for (jj = 0; jj < nb; jj++) { |
| 125 | uint32 w = k->w[j + jj]; |
| 126 | k->wi[i + jj] = MIX(U, w, w, w, w); |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | j -= nb; jj = 0; |
| 131 | for (; i < nw; i++) |
| 132 | k->wi[i] = k->w[j + jj++]; |
| 133 | } |
| 134 | |
| 135 | /*----- That's all, folks -------------------------------------------------*/ |