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d03ab969 | 1 | /* -*-c-*- |
d03ab969 | 2 | * |
3 | * The alleged RC4 stream cipher | |
4 | * | |
5 | * (c) 1999 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
d03ab969 | 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 | * |
d03ab969 | 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 | * |
d03ab969 | 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 | ||
d03ab969 | 28 | /*----- Header files ------------------------------------------------------*/ |
29 | ||
30 | #include <assert.h> | |
41f91aa3 | 31 | #include <stdarg.h> |
d03ab969 | 32 | #include <stdio.h> |
33 | ||
34 | #include <mLib/bits.h> | |
41f91aa3 | 35 | #include <mLib/sub.h> |
d03ab969 | 36 | |
4b8968dd | 37 | #include "arena.h" |
41f91aa3 | 38 | #include "gcipher.h" |
39 | #include "grand.h" | |
4b8968dd | 40 | #include "paranoia.h" |
d03ab969 | 41 | #include "rc4.h" |
42 | ||
4b8968dd | 43 | /*----- Global variables --------------------------------------------------*/ |
44 | ||
45 | const octet rc4_keysz[] = { KSZ_RANGE, RC4_KEYSZ, 1, 255, 1 }; | |
46 | ||
d03ab969 | 47 | /*----- Main code ---------------------------------------------------------*/ |
48 | ||
4b8968dd | 49 | /* --- @rc4_addkey@ --- * |
d03ab969 | 50 | * |
4b8968dd | 51 | * Arguments: @rc4_ctx *ctx@ = pointer to context to key |
d03ab969 | 52 | * @const void *k@ = pointer to key data to use |
53 | * @size_t sz@ = size of the key data | |
54 | * | |
55 | * Returns: --- | |
56 | * | |
4b8968dd | 57 | * Use: Mixes key data with an RC4 context. The RC4 context is not |
58 | * reset before mixing. This may be used to mix new key | |
59 | * material with an existing RC4 context. | |
d03ab969 | 60 | */ |
61 | ||
4b8968dd | 62 | void rc4_addkey(rc4_ctx *ctx, const void *k, size_t sz) |
d03ab969 | 63 | { |
64 | unsigned i, j; | |
65 | const octet *p = k, *q = p + sz; | |
66 | ||
4b8968dd | 67 | KSZ_ASSERT(rc4, sz); |
d03ab969 | 68 | |
d03ab969 | 69 | for (i = j = 0; i < 256; i++) { |
70 | unsigned si = ctx->s[i]; | |
71 | j = (j + si + *p++) & 0xff; | |
72 | ctx->s[i] = ctx->s[j]; | |
73 | ctx->s[j] = si; | |
74 | if (p == q) | |
75 | p = k; | |
45c0fd36 | 76 | } |
4b8968dd | 77 | |
78 | ctx->i = ctx->j = 0; | |
79 | } | |
80 | ||
81 | /* --- @rc4_init@ --- * | |
82 | * | |
83 | * Arguments: @rc4_ctx *ctx@ = pointer to context to initialize | |
84 | * @const void *k@ = pointer to key data to use | |
85 | * @size_t sz@ = size of the key data | |
86 | * | |
87 | * Returns: --- | |
88 | * | |
89 | * Use: Initializes an RC4 context ready for use. | |
90 | */ | |
91 | ||
92 | void rc4_init(rc4_ctx *ctx, const void *k, size_t sz) | |
93 | { | |
94 | unsigned i; | |
95 | ||
96 | for (i = 0; i < 256; i++) | |
97 | ctx->s[i] = i; | |
98 | ctx->f = 0; | |
99 | rc4_addkey(ctx, k, sz); | |
d03ab969 | 100 | } |
101 | ||
102 | /* --- @rc4_encrypt@ --- * | |
103 | * | |
104 | * Arguments: @rc4_ctx *ctx@ = pointer to context to use | |
105 | * @const void *src@ = pointer to the source block | |
106 | * @void *dest@ = pointer to the destination block | |
107 | * @size_t sz@ = size of the block | |
108 | * | |
109 | * Returns: --- | |
110 | * | |
111 | * Use: Encrypts or decrypts a block of data. The destination may | |
112 | * be null to just grind the generator around for a while. It's | |
113 | * recommended that you say `@rc4_encrypt(&ctx, 0, 0, 1024)@' | |
114 | * after initializing a new context, to prevent keystream | |
115 | * guessing attacks. The source may be null to just extract a | |
116 | * big lump of data from the generator. | |
117 | */ | |
118 | ||
119 | void rc4_encrypt(rc4_ctx *ctx, const void *src, void *dest, size_t sz) | |
120 | { | |
121 | const octet *s = src; | |
122 | octet *d = dest; | |
123 | ||
124 | if (!d) | |
aa02ed36 | 125 | RC4_OPEN(ctx, while (sz) { unsigned x; RC4_BYTE(x); (void)x; sz--; }); |
d03ab969 | 126 | else if (!s) |
127 | RC4_OPEN(ctx, while (sz) { RC4_BYTE(*d++); sz--; }); | |
128 | else | |
129 | RC4_OPEN(ctx, | |
130 | while (sz) { unsigned x; RC4_BYTE(x); *d++ = *s++ ^ x; sz--; }); | |
131 | } | |
132 | ||
41f91aa3 | 133 | /*----- Generic cipher interface ------------------------------------------*/ |
134 | ||
135 | typedef struct gctx { | |
136 | gcipher c; | |
137 | rc4_ctx rc4; | |
138 | } gctx; | |
139 | ||
140 | static const gcipher_ops gops; | |
141 | ||
142 | static gcipher *ginit(const void *k, size_t sz) | |
143 | { | |
4b8968dd | 144 | gctx *g = S_CREATE(gctx); |
41f91aa3 | 145 | g->c.ops = &gops; |
146 | rc4_init(&g->rc4, k, sz); | |
147 | return (&g->c); | |
148 | } | |
149 | ||
150 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) | |
151 | { | |
152 | gctx *g = (gctx *)c; | |
153 | rc4_encrypt(&g->rc4, s, t, sz); | |
154 | } | |
155 | ||
156 | static void gdestroy(gcipher *c) | |
157 | { | |
158 | gctx *g = (gctx *)c; | |
4b8968dd | 159 | BURN(*g); |
160 | S_DESTROY(g); | |
41f91aa3 | 161 | } |
162 | ||
163 | static const gcipher_ops gops = { | |
4b8968dd | 164 | &rc4, |
41f91aa3 | 165 | gencrypt, gencrypt, gdestroy, 0, 0 |
166 | }; | |
167 | ||
168 | const gccipher rc4 = { | |
4b8968dd | 169 | "rc4", rc4_keysz, 0, |
41f91aa3 | 170 | ginit |
171 | }; | |
172 | ||
173 | /*----- Generic random number generator interface -------------------------*/ | |
174 | ||
175 | typedef struct grctx { | |
176 | grand r; | |
177 | rc4_ctx rc4; | |
178 | } grctx; | |
179 | ||
180 | static void grdestroy(grand *r) | |
181 | { | |
182 | grctx *g = (grctx *)r; | |
4b8968dd | 183 | BURN(*g); |
184 | S_DESTROY(g); | |
41f91aa3 | 185 | } |
186 | ||
187 | static int grmisc(grand *r, unsigned op, ...) | |
188 | { | |
189 | grctx *g = (grctx *)r; | |
190 | va_list ap; | |
191 | int rc = 0; | |
360c232e | 192 | uint32 i; |
41f91aa3 | 193 | octet buf[4]; |
194 | va_start(ap, op); | |
195 | ||
196 | switch (op) { | |
197 | case GRAND_CHECK: | |
198 | switch (va_arg(ap, unsigned)) { | |
199 | case GRAND_CHECK: | |
200 | case GRAND_SEEDINT: | |
201 | case GRAND_SEEDUINT32: | |
202 | case GRAND_SEEDBLOCK: | |
4ab1268f | 203 | case GRAND_SEEDRAND: |
41f91aa3 | 204 | rc = 1; |
205 | break; | |
206 | default: | |
207 | rc = 0; | |
208 | break; | |
209 | } | |
210 | break; | |
211 | case GRAND_SEEDINT: | |
360c232e | 212 | i = va_arg(ap, unsigned); |
213 | STORE32(buf, i); | |
4b8968dd | 214 | rc4_addkey(&g->rc4, buf, sizeof(buf)); |
41f91aa3 | 215 | break; |
216 | case GRAND_SEEDUINT32: | |
360c232e | 217 | i = va_arg(ap, uint32); |
218 | STORE32(buf, i); | |
4b8968dd | 219 | rc4_addkey(&g->rc4, buf, sizeof(buf)); |
41f91aa3 | 220 | break; |
221 | case GRAND_SEEDBLOCK: { | |
222 | const void *p = va_arg(ap, const void *); | |
223 | size_t sz = va_arg(ap, size_t); | |
4b8968dd | 224 | rc4_addkey(&g->rc4, p, sz); |
41f91aa3 | 225 | } break; |
4ab1268f | 226 | case GRAND_SEEDRAND: { |
227 | grand *rr = va_arg(ap, grand *); | |
228 | octet buf[16]; | |
229 | rr->ops->fill(rr, buf, sizeof(buf)); | |
4b8968dd | 230 | rc4_addkey(&g->rc4, buf, sizeof(buf)); |
4ab1268f | 231 | } break; |
232 | default: | |
233 | GRAND_BADOP; | |
234 | break; | |
41f91aa3 | 235 | } |
236 | ||
237 | va_end(ap); | |
238 | return (rc); | |
239 | } | |
240 | ||
241 | static octet grbyte(grand *r) | |
242 | { | |
243 | grctx *g = (grctx *)r; | |
244 | octet o; | |
245 | RC4_OPEN(&g->rc4, RC4_BYTE(o);); | |
246 | return (o); | |
247 | } | |
248 | ||
249 | static uint32 grword(grand *r) | |
250 | { | |
251 | grctx *g = (grctx *)r; | |
252 | octet b[4]; | |
253 | int i; | |
254 | RC4_OPEN(&g->rc4, | |
255 | for (i = 0; i < sizeof(b); i++) | |
256 | RC4_BYTE(b[i]);); | |
257 | return (LOAD32(b)); | |
258 | } | |
259 | ||
260 | static void grfill(grand *r, void *p, size_t sz) | |
261 | { | |
262 | grctx *g = (grctx *)r; | |
263 | rc4_encrypt(&g->rc4, 0, p, sz); | |
264 | } | |
265 | ||
266 | static const grand_ops grops = { | |
267 | "rc4", | |
4b8968dd | 268 | GRAND_CRYPTO, 0, |
41f91aa3 | 269 | grmisc, grdestroy, |
44ff6c11 | 270 | grword, grbyte, grword, grand_defaultrange, grfill |
41f91aa3 | 271 | }; |
272 | ||
273 | /* --- @rc4_rand@ --- * | |
274 | * | |
275 | * Arguments: @const void *k@ = pointer to key material | |
276 | * @size_t sz@ = size of key material | |
277 | * | |
278 | * Returns: Pointer to generic random number generator interface. | |
279 | * | |
a620b15e MW |
280 | * Use: Creates a random number interface wrapper around the RC4 |
281 | * stream cipher. | |
41f91aa3 | 282 | */ |
283 | ||
284 | grand *rc4_rand(const void *k, size_t sz) | |
285 | { | |
4b8968dd | 286 | grctx *g = S_CREATE(grctx); |
41f91aa3 | 287 | g->r.ops = &grops; |
288 | rc4_init(&g->rc4, k, sz); | |
289 | return (&g->r); | |
290 | } | |
291 | ||
d03ab969 | 292 | /*----- Test rig ----------------------------------------------------------*/ |
293 | ||
294 | #ifdef TEST_RIG | |
295 | ||
296 | #include <stdio.h> | |
297 | #include <string.h> | |
298 | ||
141c1284 | 299 | #include <mLib/macros.h> |
d03ab969 | 300 | #include <mLib/quis.h> |
301 | #include <mLib/testrig.h> | |
302 | ||
303 | static int v_encrypt(dstr *v) | |
304 | { | |
305 | rc4_ctx ctx; | |
306 | dstr d = DSTR_INIT; | |
307 | int ok = 1; | |
308 | ||
309 | rc4_init(&ctx, v[0].buf, v[0].len); | |
310 | dstr_ensure(&d, v[1].len); | |
311 | d.len = v[1].len; | |
312 | rc4_encrypt(&ctx, v[1].buf, d.buf, d.len); | |
313 | ||
141c1284 | 314 | if (MEMCMP(v[2].buf, !=, d.buf, d.len)) { |
d03ab969 | 315 | ok = 0; |
316 | printf("\nfail encryption:" | |
45c0fd36 | 317 | "\n\tkey = "); |
d03ab969 | 318 | type_hex.dump(&v[0], stdout); |
319 | printf("\n\tplaintext = "); type_hex.dump(&v[1], stdout); | |
320 | printf("\n\texpected = "); type_hex.dump(&v[2], stdout); | |
321 | printf("\n\tcalculated = "); type_hex.dump(&d, stdout); | |
322 | putchar('\n'); | |
323 | } | |
324 | ||
325 | return (ok); | |
326 | } | |
327 | ||
328 | static int v_generate(dstr *v) | |
329 | { | |
330 | rc4_ctx ctx; | |
331 | dstr d = DSTR_INIT; | |
332 | int ok = 1; | |
333 | ||
334 | rc4_init(&ctx, v[0].buf, v[0].len); | |
335 | rc4_encrypt(&ctx, 0, 0, *(int *)v[1].buf); | |
336 | dstr_ensure(&d, v[2].len); | |
337 | d.len = v[2].len; | |
338 | rc4_encrypt(&ctx, 0, d.buf, d.len); | |
339 | ||
141c1284 | 340 | if (MEMCMP(v[2].buf, !=, d.buf, d.len)) { |
d03ab969 | 341 | ok = 0; |
342 | printf("\nfail generation:" | |
45c0fd36 | 343 | "\n\tkey = "); |
d03ab969 | 344 | type_hex.dump(&v[0], stdout); |
345 | printf("\n\tskip len = %i", *(int *)v[1].buf); | |
346 | printf("\n\texpected = "); type_hex.dump(&v[2], stdout); | |
347 | printf("\n\tcalculated = "); type_hex.dump(&d, stdout); | |
348 | putchar('\n'); | |
349 | } | |
350 | ||
351 | return (ok); | |
352 | } | |
353 | ||
354 | static test_chunk defs[] = { | |
355 | { "rc4-encrypt", v_encrypt, { &type_hex, &type_hex, &type_hex, 0 } }, | |
356 | { "rc4-generate", v_generate, { &type_hex, &type_int, &type_hex, 0 } }, | |
357 | { 0, 0, { 0 } } | |
358 | }; | |
359 | ||
360 | int main(int argc, char *argv[]) | |
361 | { | |
0f00dc4c | 362 | test_run(argc, argv, defs, SRCDIR"/t/rc4"); |
d03ab969 | 363 | return (0); |
364 | } | |
365 | ||
366 | #endif | |
367 | ||
368 | /*----- That's all, folks -------------------------------------------------*/ |