| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Build constant tables for Twofish |
| 4 | * |
| 5 | * (c) 2000 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 <stdio.h> |
| 31 | #include <stdlib.h> |
| 32 | |
| 33 | #include <mLib/bits.h> |
| 34 | |
| 35 | /*----- Data structures ---------------------------------------------------*/ |
| 36 | |
| 37 | typedef struct { octet t[4][16]; } t_tab; |
| 38 | typedef struct { octet q[256]; } q_tab; |
| 39 | |
| 40 | /*----- Various Twofish tables --------------------------------------------*/ |
| 41 | |
| 42 | /* --- The t-tables --- */ |
| 43 | |
| 44 | static const t_tab qt0 = {{ |
| 45 | { 0x8, 0x1, 0x7, 0xd, 0x6, 0xf, 0x3, 0x2, |
| 46 | 0x0, 0xb, 0x5, 0x9, 0xe, 0xc, 0xa, 0x4 }, |
| 47 | { 0xe, 0xc, 0xb, 0x8, 0x1, 0x2, 0x3, 0x5, |
| 48 | 0xf, 0x4, 0xa, 0x6, 0x7, 0x0, 0x9, 0xd }, |
| 49 | { 0xb, 0xa, 0x5, 0xe, 0x6, 0xd, 0x9, 0x0, |
| 50 | 0xc, 0x8, 0xf, 0x3, 0x2, 0x4, 0x7, 0x1 }, |
| 51 | { 0xd, 0x7, 0xf, 0x4, 0x1, 0x2, 0x6, 0xe, |
| 52 | 0x9, 0xb, 0x3, 0x0, 0x8, 0x5, 0xc, 0xa } |
| 53 | }}; |
| 54 | |
| 55 | static const t_tab qt1 = {{ |
| 56 | { 0x2, 0x8, 0xb, 0xd, 0xf, 0x7, 0x6, 0xe, |
| 57 | 0x3, 0x1, 0x9, 0x4, 0x0, 0xa, 0xc, 0x5 }, |
| 58 | { 0x1, 0xe, 0x2, 0xb, 0x4, 0xc, 0x3, 0x7, |
| 59 | 0x6, 0xd, 0xa, 0x5, 0xf, 0x9, 0x0, 0x8 }, |
| 60 | { 0x4, 0xc, 0x7, 0x5, 0x1, 0x6, 0x9, 0xa, |
| 61 | 0x0, 0xe, 0xd, 0x8, 0x2, 0xb, 0x3, 0xf }, |
| 62 | { 0xb, 0x9, 0x5, 0x1, 0xc, 0x3, 0xd, 0xe, |
| 63 | 0x6, 0x4, 0x7, 0xf, 0x2, 0x0, 0x8, 0xa } |
| 64 | }}; |
| 65 | |
| 66 | static q_tab q0, q1; |
| 67 | |
| 68 | /* --- The MDS and Reed-Solomon matrices --- */ |
| 69 | |
| 70 | static const octet mds[16] = { |
| 71 | 0x01, 0xef, 0x5b, 0x5b, |
| 72 | 0x5b, 0xef, 0xef, 0x01, |
| 73 | 0xef, 0x5b, 0x01, 0xef, |
| 74 | 0xef, 0x01, 0xef, 0x5b |
| 75 | }; |
| 76 | |
| 77 | static const octet rs[32] = { |
| 78 | 0x01, 0xa4, 0x55, 0x87, 0x5a, 0x58, 0xdb, 0x9e, |
| 79 | 0xa4, 0x56, 0x82, 0xf3, 0x1e, 0xc6, 0x68, 0xe5, |
| 80 | 0x02, 0xa1, 0xfc, 0xc1, 0x47, 0xae, 0x3d, 0x19, |
| 81 | 0xa4, 0x55, 0x87, 0x5a, 0x58, 0xdb, 0x9e, 0x03 |
| 82 | }; |
| 83 | |
| 84 | /*----- Magic macros ------------------------------------------------------*/ |
| 85 | |
| 86 | #define ROR4(x) ((((x) >> 1) | ((x) << 3)) & 15) |
| 87 | |
| 88 | /*----- Building and printing @q@ tables ----------------------------------*/ |
| 89 | |
| 90 | /* --- @mkq@ --- * |
| 91 | * |
| 92 | * Arguments: @q_tab *q@ = pointer to output @q@ table |
| 93 | * @const t_tab *t@ = pointer to input @t@ table |
| 94 | * @const char *name@ = name of @q@ table |
| 95 | * |
| 96 | * Returns: --- |
| 97 | * |
| 98 | * Use: Constructs a 256-entry @q@-table. |
| 99 | */ |
| 100 | |
| 101 | static void mkq(q_tab *q, const t_tab *t, const char *name) |
| 102 | { |
| 103 | int i; |
| 104 | int ok = 1; |
| 105 | |
| 106 | /* --- Ensure the t-table is well-formed --- */ |
| 107 | |
| 108 | for (i = 0; i < 4; i++) { |
| 109 | octet f[16] = { 0 }; |
| 110 | int j; |
| 111 | |
| 112 | for (j = 0; j < 16; j++) { |
| 113 | if (f[t->t[i][j]]) { |
| 114 | fprintf(stderr, "duplicate %i in %s[%i] (col %i and %i)\n", |
| 115 | t->t[i][j], name, i, j, f[t->t[i][j]]); |
| 116 | ok = 0; |
| 117 | } |
| 118 | f[t->t[i][j]] = j; |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | if (!ok) |
| 123 | exit(EXIT_FAILURE); |
| 124 | |
| 125 | /* --- Construct the @q@ table --- */ |
| 126 | |
| 127 | for (i = 0; i < 256; i++) { |
| 128 | int a = i >> 4, b = i & 15; |
| 129 | int aa = t->t[0][a ^ b], bb = t->t[1][a ^ ((a << 3) & 15) ^ ROR4(b)]; |
| 130 | a = t->t[2][aa ^ bb], b = t->t[3][aa ^ ((aa << 3) & 15) ^ ROR4(bb)]; |
| 131 | q->q[i] = a | (b << 4); |
| 132 | } |
| 133 | |
| 134 | /* Consider testing @q@ for linear and differential properties here */ |
| 135 | } |
| 136 | |
| 137 | /* --- @printq@ --- * |
| 138 | * |
| 139 | * Arguments: @const q_tab *t@ = pointer to table |
| 140 | * @const char *name@ = pointer to table name |
| 141 | * |
| 142 | * Returns: --- |
| 143 | * |
| 144 | * Use: Prints a q table. |
| 145 | */ |
| 146 | |
| 147 | static void printq(const q_tab *q, const char *name) |
| 148 | { |
| 149 | int i; |
| 150 | int j; |
| 151 | |
| 152 | printf("\ |
| 153 | const octet twofish_%s[256] = {\n\ |
| 154 | ", name); |
| 155 | j = 0; |
| 156 | for (i = 0; i < 256; i++) { |
| 157 | printf("0x%02x", q->q[i]); |
| 158 | j = (j + 1) & 7; |
| 159 | if (i == 255) |
| 160 | fputs("\n};\n\n", stdout); |
| 161 | else if (j == 0) |
| 162 | fputs(",\n ", stdout); |
| 163 | else |
| 164 | fputs(", ", stdout); |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | /*----- %$\gf{2^8}$% arithmetic -------------------------------------------*/ |
| 169 | |
| 170 | #define MDS_MOD 0x169 |
| 171 | #define RS_MOD 0x14d |
| 172 | |
| 173 | /* --- @mul@ --- * |
| 174 | * |
| 175 | * Arguments: @unsigned x, y@ = polynomials over %$\gf{2^8}$% |
| 176 | * @unsigned m@ = modulus |
| 177 | * |
| 178 | * Returns: The product of two polynomials. |
| 179 | * |
| 180 | * Use: Computes a product of polynomials, quite slowly. |
| 181 | */ |
| 182 | |
| 183 | static unsigned mul(unsigned x, unsigned y, unsigned m) |
| 184 | { |
| 185 | unsigned a = 0; |
| 186 | unsigned i; |
| 187 | |
| 188 | for (i = 0; i < 8; i++) { |
| 189 | if (y & 1) |
| 190 | a ^= x; |
| 191 | y >>= 1; |
| 192 | x <<= 1; |
| 193 | if (x & 0x100) |
| 194 | x ^= m; |
| 195 | } |
| 196 | |
| 197 | return (a); |
| 198 | } |
| 199 | |
| 200 | /* --- @mmul@ --- * |
| 201 | * |
| 202 | * Arguments: @octet *d@ = destination vector |
| 203 | * @const octet *p@ = matrix of bytes |
| 204 | * @const octet *q@ = vector from somewhere else |
| 205 | * @size_t r@ = size of destination or number of rows in matrix |
| 206 | * @size_t n@ = length of row and vector |
| 207 | * @unsigned m@ = modulus polynomial |
| 208 | * |
| 209 | * Returns: --- |
| 210 | * |
| 211 | * Use: Computes an inner product of matrices over the finite field |
| 212 | * %$\gf{2^8}[x]/(m(x))$%. This isn't particularly rapid. |
| 213 | */ |
| 214 | |
| 215 | static void mmul(octet *d, const octet *p, const octet *q, |
| 216 | size_t r, size_t n, unsigned m) |
| 217 | { |
| 218 | while (r) { |
| 219 | const octet *qq = q; |
| 220 | unsigned a = 0; |
| 221 | unsigned i; |
| 222 | |
| 223 | for (i = 0; i < n; i++) |
| 224 | a ^= mul(*p++, *qq++, m); |
| 225 | *d++ = a; |
| 226 | r--; |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | /* --- @qrds@ --- * |
| 231 | * |
| 232 | * Arguments: --- |
| 233 | * |
| 234 | * Returns: --- |
| 235 | * |
| 236 | * Use: Prints the MDS/q table. |
| 237 | */ |
| 238 | |
| 239 | static void qmds(void) |
| 240 | { |
| 241 | uint32 t[4][256]; |
| 242 | int i, j; |
| 243 | static const q_tab *q[4] = { &q1, &q0, &q1, &q0 }; |
| 244 | |
| 245 | for (i = 0; i < 4; i++) { |
| 246 | octet in[4] = { 0, 0, 0, 0 }; |
| 247 | octet out[4]; |
| 248 | |
| 249 | for (j = 0; j < 256; j++) { |
| 250 | in[i] = q[i]->q[j]; |
| 251 | mmul(out, mds, in, 4, 4, MDS_MOD); |
| 252 | t[i][j] = LOAD32_L(out); |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | puts("\ |
| 257 | /* --- Expanded MDS tables --- *\n\ |
| 258 | *\n\ |
| 259 | * The table contains output vectors for computing the result of pushing\n\ |
| 260 | * bytes through appropriate @q@ tables and the MDS matrix.\n\ |
| 261 | */\n\ |
| 262 | \n\ |
| 263 | const uint32 twofish_qmds[4][256] = {\ |
| 264 | "); |
| 265 | for (i = 0; i < 4; i++) { |
| 266 | fputs(" { ", stdout); |
| 267 | for (j = 0; j < 256; j++) { |
| 268 | printf("0x%08lx", (unsigned long)t[i][j]); |
| 269 | if (j == 255) { |
| 270 | if (i == 3) |
| 271 | puts(" }\n};"); |
| 272 | else |
| 273 | puts(" },\n"); |
| 274 | } else if (j % 4 == 3) |
| 275 | fputs(",\n ", stdout); |
| 276 | else |
| 277 | fputs(", ", stdout); |
| 278 | } |
| 279 | } |
| 280 | |
| 281 | putchar('\n'); |
| 282 | } |
| 283 | |
| 284 | /* --- @rslog@ --- * |
| 285 | * |
| 286 | * Arguments: --- |
| 287 | * |
| 288 | * Returns: --- |
| 289 | * |
| 290 | * Use: Produces the log and antilog tables for doing the RS |
| 291 | * arithmetic efficiently. |
| 292 | */ |
| 293 | |
| 294 | static void rslog(void) |
| 295 | { |
| 296 | octet rslog[256]; |
| 297 | octet rsexp[256]; |
| 298 | |
| 299 | unsigned x = 1; |
| 300 | unsigned i; |
| 301 | |
| 302 | rslog[0] = 0; |
| 303 | for (i = 0; i < 255; i++) { |
| 304 | rslog[x] = i; |
| 305 | rsexp[i] = x; |
| 306 | x <<= 1; |
| 307 | if (x & 0x100) |
| 308 | x ^= RS_MOD; |
| 309 | } |
| 310 | |
| 311 | x = 0; |
| 312 | for (i = 0; i < 32; i++) { |
| 313 | if (rslog[rs[i]] > x) |
| 314 | x = rslog[rs[i]]; |
| 315 | } |
| 316 | |
| 317 | fputs("\ |
| 318 | /* --- Reed-Solomon log tables --- *\n\ |
| 319 | *\n\ |
| 320 | * The Reed-Solomon multiplies are accelerated by using log tables.\n\ |
| 321 | */\n\ |
| 322 | \n\ |
| 323 | const octet twofish_rslog[256] = {\n\ |
| 324 | ", stdout); |
| 325 | |
| 326 | for (i = 0; i < 256; i++) { |
| 327 | printf("0x%02x", rslog[i]); |
| 328 | if (i == 255) |
| 329 | puts("\n};\n"); |
| 330 | else if (i % 8 == 7) |
| 331 | fputs(",\n ", stdout); |
| 332 | else |
| 333 | fputs(", ", stdout); |
| 334 | } |
| 335 | |
| 336 | printf("\ |
| 337 | const octet twofish_rsexp[%d] = {\n\ |
| 338 | ", 255 + x + 1); |
| 339 | |
| 340 | for (i = 0; i < 255 + x + 1; i++) { |
| 341 | printf("0x%02x", rsexp[i % 255]); |
| 342 | if (i == 255 + x) |
| 343 | puts("\n};\n"); |
| 344 | else if (i % 8 == 7) |
| 345 | fputs(",\n ", stdout); |
| 346 | else |
| 347 | fputs(", ", stdout); |
| 348 | } |
| 349 | |
| 350 | fputs("\ |
| 351 | /* --- Reed-Solomon matrix with log entries --- */\n\ |
| 352 | \n\ |
| 353 | const octet twofish_rs[32] = {\n\ |
| 354 | ", stdout); |
| 355 | |
| 356 | for (i = 0; i < 32; i++) { |
| 357 | printf("0x%02x", rslog[rs[i]]); |
| 358 | if (i == 31) |
| 359 | puts("\n};"); |
| 360 | else if (i % 8 == 7) |
| 361 | fputs(",\n ", stdout); |
| 362 | else |
| 363 | fputs(", ", stdout); |
| 364 | } |
| 365 | } |
| 366 | |
| 367 | /*----- Main program ------------------------------------------------------*/ |
| 368 | |
| 369 | /* --- @main@ --- */ |
| 370 | |
| 371 | int main(void) |
| 372 | { |
| 373 | fputs("\ |
| 374 | /* -*-c-*-\n\ |
| 375 | *\n\ |
| 376 | * Twofish q tables [generated]\n\ |
| 377 | */\n\ |
| 378 | \n\ |
| 379 | #include <mLib/bits.h>\n\ |
| 380 | \n\ |
| 381 | ", stdout); |
| 382 | |
| 383 | /* --- The q tables --- */ |
| 384 | |
| 385 | puts("\ |
| 386 | /* --- Precomputed @q@ tables --- */\n\ |
| 387 | "); |
| 388 | mkq(&q0, &qt0, "qt0"); |
| 389 | mkq(&q1, &qt1, "qt1"); |
| 390 | printq(&q0, "q0"); |
| 391 | printq(&q1, "q1"); |
| 392 | |
| 393 | /* --- The MDS/q tables --- */ |
| 394 | |
| 395 | qmds(); |
| 396 | rslog(); |
| 397 | |
| 398 | /* --- Done --- */ |
| 399 | |
| 400 | if (fclose(stdout)) { |
| 401 | fprintf(stderr, "error writing data\n"); |
| 402 | exit(EXIT_FAILURE); |
| 403 | } |
| 404 | |
| 405 | return (0); |
| 406 | } |
| 407 | |
| 408 | /*----- That's all, folks -------------------------------------------------*/ |