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1 | /* -*-c-*- |
2 | * |
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3 | * Build constant tables for Twofish |
4 | * |
5 | * (c) 2000 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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16 | * |
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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. |
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21 | * |
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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 | |
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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 | #define TWOFISH_%s { \\\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 | |
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168 | /*----- %$\gf{2^8}$% arithmetic -------------------------------------------*/ |
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169 | |
170 | #define MDS_MOD 0x169 |
171 | #define RS_MOD 0x14d |
172 | |
173 | /* --- @mul@ --- * |
174 | * |
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175 | * Arguments: @unsigned x, y@ = polynomials over %$\gf{2^8}$% |
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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 |
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212 | * %$\gf{2^8}[x]/(m(x))$%. This isn't particularly rapid. |
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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 | #define TWOFISH_QMDS { \\"); |
264 | for (i = 0; i < 4; i++) { |
265 | fputs(" { ", stdout); |
266 | for (j = 0; j < 256; j++) { |
267 | printf("0x%08lx", (unsigned long)t[i][j]); |
268 | if (j == 255) { |
269 | if (i == 3) |
270 | puts(" } \\\n}"); |
271 | else |
272 | puts(" }, \\\n\ |
273 | \\"); |
274 | } else if (j % 4 == 3) |
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275 | fputs(", \\\n ", stdout); |
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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; |
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303 | for (i = 0; i < 255; i++) { |
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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 | #define TWOFISH_RSLOG { \\\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 | fputs("\ |
337 | #define TWOFISH_RSEXP { \\\n\ |
338 | ", stdout); |
339 | |
340 | for (i = 0; i < 255 + x + 1; i++) { |
341 | printf("0x%02x", rsexp[i % 255]); |
342 | if (i == 255 + x) |
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343 | puts(" \\\n}\n"); |
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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 | #define TWOFISH_RS { \\\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}\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("\ |
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374 | /* -*-c-*-\n\ |
375 | *\n\ |
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376 | * Twofish q tables [generated]\n\ |
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377 | */\n\ |
378 | \n\ |
379 | #ifndef CATACOMB_TWOFISH_TAB_H\n\ |
380 | #define CATACOMB_TWOFISH_TAB_H\n\ |
381 | \n\ |
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382 | ", stdout); |
383 | |
384 | /* --- The q tables --- */ |
385 | |
386 | puts("\ |
387 | /* --- Precomputed @q@ tables --- */\n\ |
388 | "); |
389 | mkq(&q0, &qt0, "qt0"); |
390 | mkq(&q1, &qt1, "qt1"); |
391 | printq(&q0, "Q0"); |
392 | printq(&q1, "Q1"); |
393 | |
394 | /* --- The MDS/q tables --- */ |
395 | |
396 | qmds(); |
397 | rslog(); |
398 | |
399 | /* --- Done --- */ |
400 | |
401 | puts("#endif"); |
402 | |
403 | if (fclose(stdout)) { |
404 | fprintf(stderr, "error writing data\n"); |
405 | exit(EXIT_FAILURE); |
406 | } |
407 | |
408 | return (0); |
409 | } |
410 | |
411 | /*----- That's all, folks -------------------------------------------------*/ |