| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: rijndael.c,v 1.3 2001/05/07 15:44:46 mdw Exp $ |
| 4 | * |
| 5 | * The Rijndael block cipher |
| 6 | * |
| 7 | * (c) 2000 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 | /*----- Revision history --------------------------------------------------* |
| 31 | * |
| 32 | * $Log: rijndael.c,v $ |
| 33 | * Revision 1.3 2001/05/07 15:44:46 mdw |
| 34 | * Fix unusual numbers of rounds. Simplify implementation. |
| 35 | * |
| 36 | * Revision 1.2 2000/12/06 20:32:59 mdw |
| 37 | * Fix round count for weird key sizes. |
| 38 | * |
| 39 | * Revision 1.1 2000/06/17 11:56:07 mdw |
| 40 | * New cipher. |
| 41 | * |
| 42 | */ |
| 43 | |
| 44 | /*----- Header files ------------------------------------------------------*/ |
| 45 | |
| 46 | #include <assert.h> |
| 47 | #include <stdio.h> |
| 48 | |
| 49 | #include <mLib/bits.h> |
| 50 | |
| 51 | #include "blkc.h" |
| 52 | #include "gcipher.h" |
| 53 | #include "rijndael.h" |
| 54 | #include "rijndael-tab.h" |
| 55 | |
| 56 | /*----- Global variables --------------------------------------------------*/ |
| 57 | |
| 58 | const octet rijndael_keysz[] = { KSZ_RANGE, RIJNDAEL_KEYSZ, 4, 32, 4 }; |
| 59 | |
| 60 | /*----- Constant tables ---------------------------------------------------*/ |
| 61 | |
| 62 | static const octet S[256] = RIJNDAEL_S, SI[256] = RIJNDAEL_SI; |
| 63 | static const uint32 T[4][256] = RIJNDAEL_T, TI[4][256] = RIJNDAEL_TI; |
| 64 | static const uint32 U[4][256] = RIJNDAEL_U; |
| 65 | static const octet rcon[] = RIJNDAEL_RCON; |
| 66 | |
| 67 | /*----- Main code ---------------------------------------------------------*/ |
| 68 | |
| 69 | #define SUB(s, a, b, c, d) \ |
| 70 | (s[U8((a) >> 0)] << 0 | s[U8((b) >> 8)] << 8 | \ |
| 71 | s[U8((c) >> 16)] << 16 | s[U8((d) >> 24)] << 24) |
| 72 | |
| 73 | #define MIX(t, a, b, c, d) \ |
| 74 | (t[0][U8((a) >> 0)] ^ t[1][U8((b) >> 8)] ^ \ |
| 75 | t[2][U8((c) >> 16)] ^ t[3][U8((d) >> 24)]) |
| 76 | |
| 77 | /* --- @rijndael_init@ --- * |
| 78 | * |
| 79 | * Arguments: @rijndael_ctx *k@ = pointer to context to initialize |
| 80 | * @const void *buf@ = pointer to buffer of key material |
| 81 | * @size_t sz@ = size of the key material |
| 82 | * |
| 83 | * Returns: --- |
| 84 | * |
| 85 | * Use: Initializes a Rijndael context with a particular key. This |
| 86 | * implementation of Rijndael doesn't impose any particular |
| 87 | * limits on the key size except that it must be multiple of 4 |
| 88 | * bytes long. 256 bits seems sensible, though. |
| 89 | */ |
| 90 | |
| 91 | void rijndael_init(rijndael_ctx *k, const void *buf, size_t sz) |
| 92 | { |
| 93 | unsigned nk, nr, nw; |
| 94 | unsigned i, j, jj; |
| 95 | const octet *p; |
| 96 | uint32 ww; |
| 97 | |
| 98 | /* --- Sort out the key size --- */ |
| 99 | |
| 100 | KSZ_ASSERT(rijndael, sz); |
| 101 | nk = sz / 4; |
| 102 | |
| 103 | /* --- Select the number of rounds --- */ |
| 104 | |
| 105 | nr = nk + 6; |
| 106 | if (nr < 10) |
| 107 | nr = 10; |
| 108 | k->nr = nr; |
| 109 | |
| 110 | /* --- Fetch the first key words out --- */ |
| 111 | |
| 112 | p = buf; |
| 113 | for (i = 0; i < nk; i++) { |
| 114 | k->w[i] = LOAD32_L(p); |
| 115 | p += 4; |
| 116 | } |
| 117 | |
| 118 | /* --- Expand this material to fill the rest of the table --- */ |
| 119 | |
| 120 | nw = (nr + 1) * (RIJNDAEL_BLKSZ / 4); |
| 121 | ww = k->w[i - 1]; |
| 122 | p = rcon; |
| 123 | for (; i < nw; i++) { |
| 124 | uint32 w = k->w[i - nk]; |
| 125 | if (i % nk == 0) { |
| 126 | ww = ROR32(ww, 8); |
| 127 | w ^= SUB(S, ww, ww, ww, ww) ^ *p++; |
| 128 | } else if (nk > 6 && i % nk == 4) |
| 129 | w ^= SUB(S, ww, ww, ww, ww); |
| 130 | else |
| 131 | w ^= ww; |
| 132 | k->w[i] = ww = w; |
| 133 | } |
| 134 | |
| 135 | /* --- Make the decryption keys --- */ |
| 136 | |
| 137 | j = nw; |
| 138 | |
| 139 | j -= RIJNDAEL_BLKSZ / 4; jj = 0; |
| 140 | for (i = 0; i < RIJNDAEL_BLKSZ / 4; i++) |
| 141 | k->wi[i] = k->w[j + jj++]; |
| 142 | |
| 143 | for (; i < nw - RIJNDAEL_BLKSZ / 4; i += RIJNDAEL_BLKSZ / 4) { |
| 144 | j -= RIJNDAEL_BLKSZ / 4; |
| 145 | for (jj = 0; jj < RIJNDAEL_BLKSZ / 4; jj++) { |
| 146 | uint32 w = k->w[j + jj]; |
| 147 | k->wi[i + jj] = MIX(U, w, w, w, w); |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | j -= RIJNDAEL_BLKSZ / 4; jj = 0; |
| 152 | for (; i < nw; i++) |
| 153 | k->wi[i] = k->w[j + jj++]; |
| 154 | } |
| 155 | |
| 156 | /* --- @rijndael_eblk@, @rijndael_dblk@ --- * |
| 157 | * |
| 158 | * Arguments: @const rijndael_ctx *k@ = pointer to Rijndael context |
| 159 | * @const uint32 s[4]@ = pointer to source block |
| 160 | * @uint32 d[4]@ = pointer to destination block |
| 161 | * |
| 162 | * Returns: --- |
| 163 | * |
| 164 | * Use: Low-level block encryption and decryption. |
| 165 | */ |
| 166 | |
| 167 | #define DO(what, t, aa, bb, cc, dd, a, b, c, d, w) do { \ |
| 168 | aa = what(t, a, b, c, d) ^ *w++; \ |
| 169 | bb = what(t, b, c, d, a) ^ *w++; \ |
| 170 | cc = what(t, c, d, a, b) ^ *w++; \ |
| 171 | dd = what(t, d, a, b, c) ^ *w++; \ |
| 172 | } while (0) |
| 173 | |
| 174 | #define UNDO(what, t, aa, bb, cc, dd, a, b, c, d, w) do { \ |
| 175 | aa = what(t, a, d, c, b) ^ *w++; \ |
| 176 | bb = what(t, b, a, d, c) ^ *w++; \ |
| 177 | cc = what(t, c, b, a, d) ^ *w++; \ |
| 178 | dd = what(t, d, c, b, a) ^ *w++; \ |
| 179 | } while (0) |
| 180 | |
| 181 | void rijndael_eblk(const rijndael_ctx *k, const uint32 *s, uint32 *dst) |
| 182 | { |
| 183 | uint32 a = s[0], b = s[1], c = s[2], d = s[3]; |
| 184 | uint32 aa, bb, cc, dd; |
| 185 | uint32 *w = k->w; |
| 186 | |
| 187 | a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++; |
| 188 | aa = a; bb = b; cc = c; dd = d; |
| 189 | |
| 190 | switch (k->nr) { |
| 191 | case 14: |
| 192 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
| 193 | case 13: |
| 194 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
| 195 | case 12: |
| 196 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
| 197 | case 11: |
| 198 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
| 199 | case 10: |
| 200 | default: |
| 201 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
| 202 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
| 203 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
| 204 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
| 205 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
| 206 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
| 207 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
| 208 | DO(MIX, T, a, b, c, d, aa, bb, cc, dd, w); |
| 209 | DO(MIX, T, aa, bb, cc, dd, a, b, c, d, w); |
| 210 | } |
| 211 | DO(SUB, S, a, b, c, d, aa, bb, cc, dd, w); |
| 212 | |
| 213 | dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d; |
| 214 | } |
| 215 | |
| 216 | void rijndael_dblk(const rijndael_ctx *k, const uint32 *s, uint32 *dst) |
| 217 | { |
| 218 | uint32 a = s[0], b = s[1], c = s[2], d = s[3]; |
| 219 | uint32 aa, bb, cc, dd; |
| 220 | uint32 *w = k->wi; |
| 221 | |
| 222 | a ^= *w++; b ^= *w++; c ^= *w++; d ^= *w++; |
| 223 | aa = a; bb = b; cc = c; dd = d; |
| 224 | |
| 225 | switch (k->nr) { |
| 226 | case 14: |
| 227 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
| 228 | case 13: |
| 229 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
| 230 | case 12: |
| 231 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
| 232 | case 11: |
| 233 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
| 234 | case 10: |
| 235 | default: |
| 236 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
| 237 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
| 238 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
| 239 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
| 240 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
| 241 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
| 242 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
| 243 | UNDO(MIX, TI, a, b, c, d, aa, bb, cc, dd, w); |
| 244 | UNDO(MIX, TI, aa, bb, cc, dd, a, b, c, d, w); |
| 245 | } |
| 246 | UNDO(SUB, SI, a, b, c, d, aa, bb, cc, dd, w); |
| 247 | |
| 248 | dst[0] = a; dst[1] = b; dst[2] = c; dst[3] = d; |
| 249 | } |
| 250 | |
| 251 | BLKC_TEST(RIJNDAEL, rijndael) |
| 252 | |
| 253 | /*----- That's all, folks -------------------------------------------------*/ |