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3a65506d | 1 | /* -*-c-*- |
3a65506d | 2 | * |
3 | * Build precomputed tables for the Rijndael block cipher | |
4 | * | |
5 | * (c) 2000 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
3a65506d | 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. | |
45c0fd36 | 16 | * |
3a65506d | 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. | |
45c0fd36 | 21 | * |
3a65506d | 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 | ||
3a65506d | 28 | /*----- Header files ------------------------------------------------------*/ |
29 | ||
30 | #include <assert.h> | |
31 | #include <stdio.h> | |
32 | #include <stdlib.h> | |
33 | ||
34 | #include <mLib/bits.h> | |
35 | ||
36 | /*----- Magic variables ---------------------------------------------------*/ | |
37 | ||
38 | static octet s[256], si[256]; | |
39 | static uint32 t[4][256], ti[4][256]; | |
40 | static uint32 u[4][256]; | |
41 | static octet rc[32]; | |
42 | ||
43 | /*----- Main code ---------------------------------------------------------*/ | |
44 | ||
45 | /* --- @mul@ --- * | |
46 | * | |
4d47e157 | 47 | * Arguments: @unsigned x, y@ = polynomials over %$\gf{2^8}$% |
3a65506d | 48 | * @unsigned m@ = modulus |
49 | * | |
50 | * Returns: The product of two polynomials. | |
51 | * | |
52 | * Use: Computes a product of polynomials, quite slowly. | |
53 | */ | |
54 | ||
55 | static unsigned mul(unsigned x, unsigned y, unsigned m) | |
56 | { | |
57 | unsigned a = 0; | |
58 | unsigned i; | |
59 | ||
60 | for (i = 0; i < 8; i++) { | |
61 | if (y & 1) | |
62 | a ^= x; | |
63 | y >>= 1; | |
64 | x <<= 1; | |
65 | if (x & 0x100) | |
66 | x ^= m; | |
67 | } | |
68 | ||
69 | return (a); | |
70 | } | |
71 | ||
72 | /* --- @sbox@ --- * | |
73 | * | |
74 | * Build the S-box. | |
75 | * | |
4d47e157 | 76 | * This is built from inversion in the multiplicative group of |
77 | * %$\gf{2^8}[x]/(p(x))$%, where %$p(x) = x^8 + x^4 + x^3 + x + 1$%, followed | |
78 | * by an affine transformation treating inputs as vectors over %$\gf{2}$%. | |
79 | * The result is a horrible function. | |
3a65506d | 80 | * |
81 | * The inversion is done slightly sneakily, by building log and antilog | |
82 | * tables. Let %$a$% be an element of the finite field. If the inverse of | |
83 | * %$a$% is %$a^{-1}$%, then %$\log a a^{-1} = 0$%. Hence | |
84 | * %$\log a = -\log a^{-1}$%. This saves fiddling about with Euclidean | |
45c0fd36 | 85 | * algorithm. |
3a65506d | 86 | */ |
87 | ||
88 | #define S_MOD 0x11b | |
89 | ||
90 | static void sbox(void) | |
91 | { | |
92 | octet log[256], alog[256]; | |
93 | unsigned x; | |
94 | unsigned i; | |
95 | unsigned g; | |
96 | ||
97 | /* --- Find a suitable generator, and build log tables --- */ | |
98 | ||
99 | log[0] = 0; | |
100 | for (g = 2; g < 256; g++) { | |
101 | x = 1; | |
102 | for (i = 0; i < 256; i++) { | |
103 | log[x] = i; | |
104 | alog[i] = x; | |
105 | x = mul(x, g, S_MOD); | |
106 | if (x == 1 && i != 254) | |
107 | goto again; | |
108 | } | |
109 | goto done; | |
110 | again:; | |
111 | } | |
112 | fprintf(stderr, "couldn't find generator\n"); | |
113 | exit(EXIT_FAILURE); | |
114 | done:; | |
115 | ||
116 | /* --- Now grind through and do the affine transform --- * | |
117 | * | |
118 | * The matrix multiply is an AND and a parity op. The add is an XOR. | |
119 | */ | |
120 | ||
121 | for (i = 0; i < 256; i++) { | |
122 | unsigned j; | |
123 | unsigned m = 0xf8; | |
124 | unsigned v = i ? alog[255 - log[i]] : 0; | |
125 | ||
126 | assert(i == 0 || mul(i, v, S_MOD) == 1); | |
127 | ||
128 | x = 0; | |
129 | for (j = 0; j < 8; j++) { | |
130 | unsigned r; | |
131 | r = v & m; | |
132 | r = (r >> 4) ^ r; | |
133 | r = (r >> 2) ^ r; | |
134 | r = (r >> 1) ^ r; | |
135 | x = (x << 1) | (r & 1); | |
136 | m = ROR8(m, 1); | |
137 | } | |
138 | x ^= 0x63; | |
139 | s[i] = x; | |
140 | si[x] = i; | |
141 | } | |
142 | } | |
143 | ||
144 | /* --- @tbox@ --- * | |
145 | * | |
146 | * Construct the t tables for doing the round function efficiently. | |
147 | */ | |
148 | ||
149 | static void tbox(void) | |
150 | { | |
151 | unsigned i; | |
152 | ||
153 | for (i = 0; i < 256; i++) { | |
154 | uint32 a, b, c, d; | |
155 | uint32 w; | |
156 | ||
157 | /* --- Build a forwards t-box entry --- */ | |
158 | ||
159 | a = s[i]; | |
160 | b = a << 1; if (b & 0x100) b ^= S_MOD; | |
161 | c = a ^ b; | |
38333dc2 | 162 | w = (c << 0) | (a << 8) | (a << 16) | (b << 24); |
3a65506d | 163 | t[0][i] = w; |
38333dc2 MW |
164 | t[1][i] = ROR32(w, 8); |
165 | t[2][i] = ROR32(w, 16); | |
166 | t[3][i] = ROR32(w, 24); | |
3a65506d | 167 | |
168 | /* --- Build a backwards t-box entry --- */ | |
169 | ||
170 | a = mul(si[i], 0x0e, S_MOD); | |
171 | b = mul(si[i], 0x09, S_MOD); | |
172 | c = mul(si[i], 0x0d, S_MOD); | |
173 | d = mul(si[i], 0x0b, S_MOD); | |
38333dc2 | 174 | w = (d << 0) | (c << 8) | (b << 16) | (a << 24); |
3a65506d | 175 | ti[0][i] = w; |
38333dc2 MW |
176 | ti[1][i] = ROR32(w, 8); |
177 | ti[2][i] = ROR32(w, 16); | |
178 | ti[3][i] = ROR32(w, 24); | |
3a65506d | 179 | } |
180 | } | |
181 | ||
182 | /* --- @ubox@ --- * | |
183 | * | |
184 | * Construct the tables for performing the decryption key schedule. | |
185 | */ | |
186 | ||
187 | static void ubox(void) | |
188 | { | |
189 | unsigned i; | |
190 | ||
191 | for (i = 0; i < 256; i++) { | |
192 | uint32 a, b, c, d; | |
193 | uint32 w; | |
194 | a = mul(i, 0x0e, S_MOD); | |
195 | b = mul(i, 0x09, S_MOD); | |
196 | c = mul(i, 0x0d, S_MOD); | |
197 | d = mul(i, 0x0b, S_MOD); | |
38333dc2 | 198 | w = (d << 0) | (c << 8) | (b << 16) | (a << 24); |
3a65506d | 199 | u[0][i] = w; |
38333dc2 MW |
200 | u[1][i] = ROR32(w, 8); |
201 | u[2][i] = ROR32(w, 16); | |
202 | u[3][i] = ROR32(w, 24); | |
3a65506d | 203 | } |
204 | } | |
205 | ||
206 | /* --- Round constants --- */ | |
207 | ||
7a28dc19 | 208 | static void rcon(void) |
3a65506d | 209 | { |
210 | unsigned r = 1; | |
211 | int i; | |
212 | ||
213 | for (i = 0; i < sizeof(rc); i++) { | |
214 | rc[i] = r; | |
215 | r <<= 1; | |
216 | if (r & 0x100) | |
217 | r ^= S_MOD; | |
218 | } | |
219 | } | |
220 | ||
221 | /* --- @main@ --- */ | |
222 | ||
223 | int main(void) | |
224 | { | |
225 | int i, j; | |
226 | ||
227 | puts("\ | |
228 | /* -*-c-*-\n\ | |
229 | *\n\ | |
230 | * Rijndael tables [generated]\n\ | |
231 | */\n\ | |
232 | \n\ | |
e5b61a8d | 233 | #include \"rijndael-base.h\"\n\ |
3a65506d | 234 | "); |
235 | ||
236 | /* --- Write out the S-box --- */ | |
237 | ||
238 | sbox(); | |
239 | fputs("\ | |
240 | /* --- The byte substitution and its inverse --- */\n\ | |
241 | \n\ | |
e5b61a8d | 242 | const octet rijndael_s[256] = {\n\ |
3a65506d | 243 | ", stdout); |
244 | for (i = 0; i < 256; i++) { | |
245 | printf("0x%02x", s[i]); | |
246 | if (i == 255) | |
e5b61a8d | 247 | fputs("\n};\n\n", stdout); |
3a65506d | 248 | else if (i % 8 == 7) |
e5b61a8d | 249 | fputs(",\n ", stdout); |
3a65506d | 250 | else |
251 | fputs(", ", stdout); | |
252 | } | |
253 | ||
254 | fputs("\ | |
e5b61a8d | 255 | const octet rijndael_si[256] = {\n\ |
3a65506d | 256 | ", stdout); |
257 | for (i = 0; i < 256; i++) { | |
258 | printf("0x%02x", si[i]); | |
259 | if (i == 255) | |
e5b61a8d | 260 | fputs("\n};\n\n", stdout); |
3a65506d | 261 | else if (i % 8 == 7) |
e5b61a8d | 262 | fputs(",\n ", stdout); |
3a65506d | 263 | else |
264 | fputs(", ", stdout); | |
265 | } | |
266 | ||
267 | /* --- Write out the big t tables --- */ | |
268 | ||
269 | tbox(); | |
270 | fputs("\ | |
271 | /* --- The big round tables --- */\n\ | |
272 | \n\ | |
e5b61a8d | 273 | const uint32 rijndael_t[4][256] = {\n\ |
3a65506d | 274 | { ", stdout); |
275 | for (j = 0; j < 4; j++) { | |
276 | for (i = 0; i < 256; i++) { | |
7a28dc19 | 277 | printf("0x%08lx", (unsigned long)t[j][i]); |
3a65506d | 278 | if (i == 255) { |
279 | if (j == 3) | |
e5b61a8d | 280 | fputs(" }\n};\n\n", stdout); |
3a65506d | 281 | else |
e5b61a8d | 282 | fputs(" },\n\n { ", stdout); |
3a65506d | 283 | } else if (i % 4 == 3) |
e5b61a8d | 284 | fputs(",\n ", stdout); |
3a65506d | 285 | else |
286 | fputs(", ", stdout); | |
287 | } | |
45c0fd36 | 288 | } |
3a65506d | 289 | |
290 | fputs("\ | |
e5b61a8d | 291 | const uint32 rijndael_ti[4][256] = {\n\ |
3a65506d | 292 | { ", stdout); |
293 | for (j = 0; j < 4; j++) { | |
294 | for (i = 0; i < 256; i++) { | |
7a28dc19 | 295 | printf("0x%08lx", (unsigned long)ti[j][i]); |
3a65506d | 296 | if (i == 255) { |
297 | if (j == 3) | |
e5b61a8d | 298 | fputs(" }\n};\n\n", stdout); |
3a65506d | 299 | else |
e5b61a8d | 300 | fputs(" },\n\n { ", stdout); |
3a65506d | 301 | } else if (i % 4 == 3) |
e5b61a8d | 302 | fputs(",\n ", stdout); |
3a65506d | 303 | else |
304 | fputs(", ", stdout); | |
305 | } | |
306 | } | |
307 | ||
308 | /* --- Write out the big u tables --- */ | |
309 | ||
310 | ubox(); | |
311 | fputs("\ | |
312 | /* --- The decryption key schedule tables --- */\n\ | |
313 | \n\ | |
e5b61a8d | 314 | const uint32 rijndael_u[4][256] = {\n\ |
3a65506d | 315 | { ", stdout); |
316 | for (j = 0; j < 4; j++) { | |
317 | for (i = 0; i < 256; i++) { | |
7a28dc19 | 318 | printf("0x%08lx", (unsigned long)u[j][i]); |
3a65506d | 319 | if (i == 255) { |
320 | if (j == 3) | |
e5b61a8d | 321 | fputs(" }\n};\n\n", stdout); |
3a65506d | 322 | else |
e5b61a8d | 323 | fputs(" },\n\n { ", stdout); |
3a65506d | 324 | } else if (i % 4 == 3) |
e5b61a8d | 325 | fputs(",\n ", stdout); |
3a65506d | 326 | else |
327 | fputs(", ", stdout); | |
328 | } | |
45c0fd36 | 329 | } |
3a65506d | 330 | |
331 | /* --- Round constants --- */ | |
332 | ||
333 | rcon(); | |
334 | fputs("\ | |
335 | /* --- The round constants --- */\n\ | |
336 | \n\ | |
e5b61a8d | 337 | const octet rijndael_rcon[32] = {\n\ |
3a65506d | 338 | ", stdout); |
339 | for (i = 0; i < sizeof(rc); i++) { | |
340 | printf("0x%02x", rc[i]); | |
341 | if (i == sizeof(rc) - 1) | |
e5b61a8d | 342 | fputs("\n};\n", stdout); |
3a65506d | 343 | else if (i % 8 == 7) |
e5b61a8d | 344 | fputs(",\n ", stdout); |
3a65506d | 345 | else |
346 | fputs(", ", stdout); | |
45c0fd36 | 347 | } |
3a65506d | 348 | |
349 | /* --- Done --- */ | |
350 | ||
3a65506d | 351 | if (fclose(stdout)) { |
352 | fprintf(stderr, "error writing data\n"); | |
353 | exit(EXIT_FAILURE); | |
354 | } | |
355 | ||
356 | return (0); | |
357 | } | |
358 | ||
359 | /*----- That's all, folks -------------------------------------------------*/ |