| 1 | /*- |
| 2 | * Copyright (c) 1991 The Regents of the University of California. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * 3. All advertising materials mentioning features or use of this software |
| 14 | * must display the following acknowledgement: |
| 15 | * This product includes software developed by the University of |
| 16 | * California, Berkeley and its contributors. |
| 17 | * 4. Neither the name of the University nor the names of its contributors |
| 18 | * may be used to endorse or promote products derived from this software |
| 19 | * without specific prior written permission. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 31 | * SUCH DAMAGE. |
| 32 | */ |
| 33 | |
| 34 | #ifndef lint |
| 35 | static char sccsid[] = "@(#)enc_des.c 5.1 (Berkeley) 3/22/91"; |
| 36 | #endif /* not lint */ |
| 37 | |
| 38 | #if defined(AUTHENTICATE) && defined(ENCRYPT) && defined(DES_ENCRYPT) |
| 39 | #include <arpa/telnet.h> |
| 40 | #include <stdio.h> |
| 41 | #ifdef __STDC__ |
| 42 | #include <stdlib.h> |
| 43 | #endif |
| 44 | |
| 45 | #include "encrypt.h" |
| 46 | #include "key-proto.h" |
| 47 | #include "misc-proto.h" |
| 48 | |
| 49 | extern encrypt_debug_mode; |
| 50 | |
| 51 | #define CFB 0 |
| 52 | #define OFB 1 |
| 53 | |
| 54 | #define NO_SEND_IV 1 |
| 55 | #define NO_RECV_IV 2 |
| 56 | #define NO_KEYID 4 |
| 57 | #define IN_PROGRESS (NO_SEND_IV|NO_RECV_IV|NO_KEYID) |
| 58 | #define SUCCESS 0 |
| 59 | #define FAILED -1 |
| 60 | |
| 61 | |
| 62 | struct fb { |
| 63 | Block krbdes_key; |
| 64 | Schedule krbdes_sched; |
| 65 | Block temp_feed; |
| 66 | unsigned char fb_feed[64]; |
| 67 | int need_start; |
| 68 | int state[2]; |
| 69 | int keyid[2]; |
| 70 | int once; |
| 71 | struct stinfo { |
| 72 | Block str_output; |
| 73 | Block str_feed; |
| 74 | Block str_iv; |
| 75 | Block str_ikey; |
| 76 | Schedule str_sched; |
| 77 | int str_index; |
| 78 | int str_flagshift; |
| 79 | } streams[2]; |
| 80 | }; |
| 81 | |
| 82 | static struct fb fb[2]; |
| 83 | |
| 84 | struct keyidlist { |
| 85 | char *keyid; |
| 86 | int keyidlen; |
| 87 | char *key; |
| 88 | int keylen; |
| 89 | int flags; |
| 90 | } keyidlist [] = { |
| 91 | { "\0", 1, 0, 0, 0 }, /* default key of zero */ |
| 92 | { 0, 0, 0, 0, 0 } |
| 93 | }; |
| 94 | |
| 95 | #define KEYFLAG_MASK 03 |
| 96 | |
| 97 | #define KEYFLAG_NOINIT 00 |
| 98 | #define KEYFLAG_INIT 01 |
| 99 | #define KEYFLAG_OK 02 |
| 100 | #define KEYFLAG_BAD 03 |
| 101 | |
| 102 | #define KEYFLAG_SHIFT 2 |
| 103 | |
| 104 | #define SHIFT_VAL(a,b) (KEYFLAG_SHIFT*((a)+((b)*2))) |
| 105 | |
| 106 | #define FB64_IV 1 |
| 107 | #define FB64_IV_OK 2 |
| 108 | #define FB64_IV_BAD 3 |
| 109 | |
| 110 | |
| 111 | void fb64_stream_iv P((Block, struct stinfo *)); |
| 112 | void fb64_init P((struct fb *)); |
| 113 | int fb64_start P((struct fb *, int, int)); |
| 114 | int fb64_is P((unsigned char *, int, struct fb *)); |
| 115 | int fb64_reply P((unsigned char *, int, struct fb *)); |
| 116 | void fb64_session P((Session_Key *, int, struct fb *)); |
| 117 | void fb64_stream_key P((Block, struct stinfo *)); |
| 118 | int fb64_keyid P((int, unsigned char *, int *, struct fb *)); |
| 119 | |
| 120 | void |
| 121 | cfb64_init(server) |
| 122 | int server; |
| 123 | { |
| 124 | fb64_init(&fb[CFB]); |
| 125 | fb[CFB].fb_feed[4] = ENCTYPE_DES_CFB64; |
| 126 | fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, CFB); |
| 127 | fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, CFB); |
| 128 | } |
| 129 | |
| 130 | void |
| 131 | ofb64_init(server) |
| 132 | int server; |
| 133 | { |
| 134 | fb64_init(&fb[OFB]); |
| 135 | fb[OFB].fb_feed[4] = ENCTYPE_DES_OFB64; |
| 136 | fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, OFB); |
| 137 | fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, OFB); |
| 138 | } |
| 139 | |
| 140 | void |
| 141 | fb64_init(fbp) |
| 142 | register struct fb *fbp; |
| 143 | { |
| 144 | bzero((void *)fbp, sizeof(*fbp)); |
| 145 | fbp->state[0] = fbp->state[1] = FAILED; |
| 146 | fbp->fb_feed[0] = IAC; |
| 147 | fbp->fb_feed[1] = SB; |
| 148 | fbp->fb_feed[2] = TELOPT_ENCRYPT; |
| 149 | fbp->fb_feed[3] = ENCRYPT_IS; |
| 150 | } |
| 151 | |
| 152 | /* |
| 153 | * Returns: |
| 154 | * -1: some error. Negotiation is done, encryption not ready. |
| 155 | * 0: Successful, initial negotiation all done. |
| 156 | * 1: successful, negotiation not done yet. |
| 157 | * 2: Not yet. Other things (like getting the key from |
| 158 | * Kerberos) have to happen before we can continue. |
| 159 | */ |
| 160 | int |
| 161 | cfb64_start(dir, server) |
| 162 | int dir; |
| 163 | int server; |
| 164 | { |
| 165 | return(fb64_start(&fb[CFB], dir, server)); |
| 166 | } |
| 167 | int |
| 168 | ofb64_start(dir, server) |
| 169 | int dir; |
| 170 | int server; |
| 171 | { |
| 172 | return(fb64_start(&fb[OFB], dir, server)); |
| 173 | } |
| 174 | |
| 175 | static int |
| 176 | fb64_start(fbp, dir, server) |
| 177 | struct fb *fbp; |
| 178 | int dir; |
| 179 | int server; |
| 180 | { |
| 181 | Block b; |
| 182 | int x; |
| 183 | unsigned char *p; |
| 184 | register int state; |
| 185 | |
| 186 | switch (dir) { |
| 187 | case DIR_DECRYPT: |
| 188 | /* |
| 189 | * This is simply a request to have the other side |
| 190 | * start output (our input). He will negotiate an |
| 191 | * IV so we need not look for it. |
| 192 | */ |
| 193 | state = fbp->state[dir-1]; |
| 194 | if (state == FAILED) |
| 195 | state = IN_PROGRESS; |
| 196 | break; |
| 197 | |
| 198 | case DIR_ENCRYPT: |
| 199 | state = fbp->state[dir-1]; |
| 200 | if (state == FAILED) |
| 201 | state = IN_PROGRESS; |
| 202 | else if ((state & NO_SEND_IV) == 0) |
| 203 | break; |
| 204 | |
| 205 | if (!VALIDKEY(fbp->krbdes_key)) { |
| 206 | fbp->need_start = 1; |
| 207 | break; |
| 208 | } |
| 209 | state &= ~NO_SEND_IV; |
| 210 | state |= NO_RECV_IV; |
| 211 | if (encrypt_debug_mode) |
| 212 | printf("Creating new feed\r\n"); |
| 213 | /* |
| 214 | * Create a random feed and send it over. |
| 215 | */ |
| 216 | des_new_random_key(fbp->temp_feed); |
| 217 | des_ecb_encrypt(fbp->temp_feed, fbp->temp_feed, |
| 218 | fbp->krbdes_sched, 1); |
| 219 | p = fbp->fb_feed + 3; |
| 220 | *p++ = ENCRYPT_IS; |
| 221 | p++; |
| 222 | *p++ = FB64_IV; |
| 223 | for (x = 0; x < sizeof(Block); ++x) { |
| 224 | if ((*p++ = fbp->temp_feed[x]) == IAC) |
| 225 | *p++ = IAC; |
| 226 | } |
| 227 | *p++ = IAC; |
| 228 | *p++ = SE; |
| 229 | printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); |
| 230 | net_write(fbp->fb_feed, p - fbp->fb_feed); |
| 231 | break; |
| 232 | default: |
| 233 | return(FAILED); |
| 234 | } |
| 235 | return(fbp->state[dir-1] = state); |
| 236 | } |
| 237 | |
| 238 | /* |
| 239 | * Returns: |
| 240 | * -1: some error. Negotiation is done, encryption not ready. |
| 241 | * 0: Successful, initial negotiation all done. |
| 242 | * 1: successful, negotiation not done yet. |
| 243 | */ |
| 244 | int |
| 245 | cfb64_is(data, cnt) |
| 246 | unsigned char *data; |
| 247 | int cnt; |
| 248 | { |
| 249 | return(fb64_is(data, cnt, &fb[CFB])); |
| 250 | } |
| 251 | int |
| 252 | ofb64_is(data, cnt) |
| 253 | unsigned char *data; |
| 254 | int cnt; |
| 255 | { |
| 256 | return(fb64_is(data, cnt, &fb[OFB])); |
| 257 | } |
| 258 | |
| 259 | int |
| 260 | fb64_is(data, cnt, fbp) |
| 261 | unsigned char *data; |
| 262 | int cnt; |
| 263 | struct fb *fbp; |
| 264 | { |
| 265 | int x; |
| 266 | unsigned char *p; |
| 267 | Block b; |
| 268 | register int state = fbp->state[DIR_DECRYPT-1]; |
| 269 | |
| 270 | if (cnt-- < 1) |
| 271 | goto failure; |
| 272 | |
| 273 | switch (*data++) { |
| 274 | case FB64_IV: |
| 275 | if (cnt != sizeof(Block)) { |
| 276 | if (encrypt_debug_mode) |
| 277 | printf("CFB64: initial vector failed on size\r\n"); |
| 278 | state = FAILED; |
| 279 | goto failure; |
| 280 | } |
| 281 | |
| 282 | if (encrypt_debug_mode) |
| 283 | printf("CFB64: initial vector received\r\n"); |
| 284 | |
| 285 | if (encrypt_debug_mode) |
| 286 | printf("Initializing Decrypt stream\r\n"); |
| 287 | |
| 288 | fb64_stream_iv((void *)data, &fbp->streams[DIR_DECRYPT-1]); |
| 289 | |
| 290 | p = fbp->fb_feed + 3; |
| 291 | *p++ = ENCRYPT_REPLY; |
| 292 | p++; |
| 293 | *p++ = FB64_IV_OK; |
| 294 | *p++ = IAC; |
| 295 | *p++ = SE; |
| 296 | printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); |
| 297 | net_write(fbp->fb_feed, p - fbp->fb_feed); |
| 298 | |
| 299 | state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS; |
| 300 | break; |
| 301 | |
| 302 | default: |
| 303 | if (encrypt_debug_mode) { |
| 304 | printf("Unknown option type: %d\r\n", *(data-1)); |
| 305 | printd(data, cnt); |
| 306 | printf("\r\n"); |
| 307 | } |
| 308 | /* FALL THROUGH */ |
| 309 | failure: |
| 310 | /* |
| 311 | * We failed. Send an FB64_IV_BAD option |
| 312 | * to the other side so it will know that |
| 313 | * things failed. |
| 314 | */ |
| 315 | p = fbp->fb_feed + 3; |
| 316 | *p++ = ENCRYPT_REPLY; |
| 317 | p++; |
| 318 | *p++ = FB64_IV_BAD; |
| 319 | *p++ = IAC; |
| 320 | *p++ = SE; |
| 321 | printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); |
| 322 | net_write(fbp->fb_feed, p - fbp->fb_feed); |
| 323 | |
| 324 | break; |
| 325 | } |
| 326 | return(fbp->state[DIR_DECRYPT-1] = state); |
| 327 | } |
| 328 | |
| 329 | /* |
| 330 | * Returns: |
| 331 | * -1: some error. Negotiation is done, encryption not ready. |
| 332 | * 0: Successful, initial negotiation all done. |
| 333 | * 1: successful, negotiation not done yet. |
| 334 | */ |
| 335 | int |
| 336 | cfb64_reply(data, cnt) |
| 337 | unsigned char *data; |
| 338 | int cnt; |
| 339 | { |
| 340 | return(fb64_reply(data, cnt, &fb[CFB])); |
| 341 | } |
| 342 | int |
| 343 | ofb64_reply(data, cnt) |
| 344 | unsigned char *data; |
| 345 | int cnt; |
| 346 | { |
| 347 | return(fb64_reply(data, cnt, &fb[OFB])); |
| 348 | } |
| 349 | |
| 350 | |
| 351 | int |
| 352 | fb64_reply(data, cnt, fbp) |
| 353 | unsigned char *data; |
| 354 | int cnt; |
| 355 | struct fb *fbp; |
| 356 | { |
| 357 | int x; |
| 358 | unsigned char *p; |
| 359 | Block b; |
| 360 | register int state = fbp->state[DIR_ENCRYPT-1]; |
| 361 | |
| 362 | if (cnt-- < 1) |
| 363 | goto failure; |
| 364 | |
| 365 | switch (*data++) { |
| 366 | case FB64_IV_OK: |
| 367 | fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); |
| 368 | if (state == FAILED) |
| 369 | state = IN_PROGRESS; |
| 370 | state &= ~NO_RECV_IV; |
| 371 | encrypt_send_keyid(DIR_ENCRYPT, (unsigned char *)"\0", 1, 1); |
| 372 | break; |
| 373 | |
| 374 | case FB64_IV_BAD: |
| 375 | bzero(fbp->temp_feed, sizeof(Block)); |
| 376 | fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); |
| 377 | state = FAILED; |
| 378 | break; |
| 379 | |
| 380 | default: |
| 381 | if (encrypt_debug_mode) { |
| 382 | printf("Unknown option type: %d\r\n", data[-1]); |
| 383 | printd(data, cnt); |
| 384 | printf("\r\n"); |
| 385 | } |
| 386 | /* FALL THROUGH */ |
| 387 | failure: |
| 388 | state = FAILED; |
| 389 | break; |
| 390 | } |
| 391 | return(fbp->state[DIR_ENCRYPT-1] = state); |
| 392 | } |
| 393 | |
| 394 | void |
| 395 | cfb64_session(key, server) |
| 396 | Session_Key *key; |
| 397 | int server; |
| 398 | { |
| 399 | fb64_session(key, server, &fb[CFB]); |
| 400 | } |
| 401 | |
| 402 | void |
| 403 | ofb64_session(key, server) |
| 404 | Session_Key *key; |
| 405 | int server; |
| 406 | { |
| 407 | fb64_session(key, server, &fb[OFB]); |
| 408 | } |
| 409 | |
| 410 | static void |
| 411 | fb64_session(key, server, fbp) |
| 412 | Session_Key *key; |
| 413 | int server; |
| 414 | struct fb *fbp; |
| 415 | { |
| 416 | |
| 417 | if (!key || key->type != SK_DES) { |
| 418 | if (encrypt_debug_mode) |
| 419 | printf("Can't set krbdes's session key (%d != %d)\r\n", |
| 420 | key ? key->type : -1, SK_DES); |
| 421 | return; |
| 422 | } |
| 423 | bcopy((void *)key->data, (void *)fbp->krbdes_key, sizeof(Block)); |
| 424 | |
| 425 | fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]); |
| 426 | fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]); |
| 427 | |
| 428 | if (fbp->once == 0) { |
| 429 | des_set_random_generator_seed(fbp->krbdes_key); |
| 430 | fbp->once = 1; |
| 431 | } |
| 432 | des_key_sched(fbp->krbdes_key, fbp->krbdes_sched); |
| 433 | /* |
| 434 | * Now look to see if krbdes_start() was was waiting for |
| 435 | * the key to show up. If so, go ahead an call it now |
| 436 | * that we have the key. |
| 437 | */ |
| 438 | if (fbp->need_start) { |
| 439 | fbp->need_start = 0; |
| 440 | fb64_start(fbp, DIR_ENCRYPT, server); |
| 441 | } |
| 442 | } |
| 443 | |
| 444 | /* |
| 445 | * We only accept a keyid of 0. If we get a keyid of |
| 446 | * 0, then mark the state as SUCCESS. |
| 447 | */ |
| 448 | int |
| 449 | cfb64_keyid(dir, kp, lenp) |
| 450 | int dir, *lenp; |
| 451 | unsigned char *kp; |
| 452 | { |
| 453 | return(fb64_keyid(dir, kp, lenp, &fb[CFB])); |
| 454 | } |
| 455 | |
| 456 | int |
| 457 | ofb64_keyid(dir, kp, lenp) |
| 458 | int dir, *lenp; |
| 459 | unsigned char *kp; |
| 460 | { |
| 461 | return(fb64_keyid(dir, kp, lenp, &fb[OFB])); |
| 462 | } |
| 463 | |
| 464 | int |
| 465 | fb64_keyid(dir, kp, lenp, fbp) |
| 466 | int dir, *lenp; |
| 467 | unsigned char *kp; |
| 468 | struct fb *fbp; |
| 469 | { |
| 470 | register int state = fbp->state[dir-1]; |
| 471 | |
| 472 | if (*lenp != 1 || (*kp != '\0')) { |
| 473 | *lenp = 0; |
| 474 | return(state); |
| 475 | } |
| 476 | |
| 477 | if (state == FAILED) |
| 478 | state = IN_PROGRESS; |
| 479 | |
| 480 | state &= ~NO_KEYID; |
| 481 | |
| 482 | return(fbp->state[dir-1] = state); |
| 483 | } |
| 484 | |
| 485 | void |
| 486 | fb64_printsub(data, cnt, buf, buflen, type) |
| 487 | unsigned char *data, *buf, *type; |
| 488 | int cnt, buflen; |
| 489 | { |
| 490 | char lbuf[32]; |
| 491 | register int i; |
| 492 | char *cp; |
| 493 | |
| 494 | buf[buflen-1] = '\0'; /* make sure it's NULL terminated */ |
| 495 | buflen -= 1; |
| 496 | |
| 497 | switch(data[2]) { |
| 498 | case FB64_IV: |
| 499 | sprintf(lbuf, "%s_IV", type); |
| 500 | cp = lbuf; |
| 501 | goto common; |
| 502 | |
| 503 | case FB64_IV_OK: |
| 504 | sprintf(lbuf, "%s_IV_OK", type); |
| 505 | cp = lbuf; |
| 506 | goto common; |
| 507 | |
| 508 | case FB64_IV_BAD: |
| 509 | sprintf(lbuf, "%s_IV_BAD", type); |
| 510 | cp = lbuf; |
| 511 | goto common; |
| 512 | |
| 513 | default: |
| 514 | sprintf(lbuf, " %d (unknown)", data[2]); |
| 515 | cp = lbuf; |
| 516 | common: |
| 517 | for (; (buflen > 0) && (*buf = *cp++); buf++) |
| 518 | buflen--; |
| 519 | for (i = 3; i < cnt; i++) { |
| 520 | sprintf(lbuf, " %d", data[i]); |
| 521 | for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++) |
| 522 | buflen--; |
| 523 | } |
| 524 | break; |
| 525 | } |
| 526 | } |
| 527 | |
| 528 | void |
| 529 | cfb64_printsub(data, cnt, buf, buflen) |
| 530 | unsigned char *data, *buf; |
| 531 | int cnt, buflen; |
| 532 | { |
| 533 | fb64_printsub(data, cnt, buf, buflen, "CFB64"); |
| 534 | } |
| 535 | |
| 536 | void |
| 537 | ofb64_printsub(data, cnt, buf, buflen) |
| 538 | unsigned char *data, *buf; |
| 539 | int cnt, buflen; |
| 540 | { |
| 541 | fb64_printsub(data, cnt, buf, buflen, "OFB64"); |
| 542 | } |
| 543 | |
| 544 | void |
| 545 | fb64_stream_iv(seed, stp) |
| 546 | Block seed; |
| 547 | register struct stinfo *stp; |
| 548 | { |
| 549 | |
| 550 | bcopy((void *)seed, (void *)stp->str_iv, sizeof(Block)); |
| 551 | bcopy((void *)seed, (void *)stp->str_output, sizeof(Block)); |
| 552 | |
| 553 | des_key_sched(stp->str_ikey, stp->str_sched); |
| 554 | |
| 555 | stp->str_index = sizeof(Block); |
| 556 | } |
| 557 | |
| 558 | void |
| 559 | fb64_stream_key(key, stp) |
| 560 | Block key; |
| 561 | register struct stinfo *stp; |
| 562 | { |
| 563 | bcopy((void *)key, (void *)stp->str_ikey, sizeof(Block)); |
| 564 | des_key_sched(key, stp->str_sched); |
| 565 | |
| 566 | bcopy((void *)stp->str_iv, (void *)stp->str_output, sizeof(Block)); |
| 567 | |
| 568 | stp->str_index = sizeof(Block); |
| 569 | } |
| 570 | |
| 571 | /* |
| 572 | * DES 64 bit Cipher Feedback |
| 573 | * |
| 574 | * key --->+-----+ |
| 575 | * +->| DES |--+ |
| 576 | * | +-----+ | |
| 577 | * | v |
| 578 | * INPUT --(--------->(+)+---> DATA |
| 579 | * | | |
| 580 | * +-------------+ |
| 581 | * |
| 582 | * |
| 583 | * Given: |
| 584 | * iV: Initial vector, 64 bits (8 bytes) long. |
| 585 | * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). |
| 586 | * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. |
| 587 | * |
| 588 | * V0 = DES(iV, key) |
| 589 | * On = Dn ^ Vn |
| 590 | * V(n+1) = DES(On, key) |
| 591 | */ |
| 592 | |
| 593 | void |
| 594 | cfb64_encrypt(s, c) |
| 595 | register unsigned char *s; |
| 596 | int c; |
| 597 | { |
| 598 | register struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1]; |
| 599 | register int index; |
| 600 | |
| 601 | index = stp->str_index; |
| 602 | while (c-- > 0) { |
| 603 | if (index == sizeof(Block)) { |
| 604 | Block b; |
| 605 | des_ecb_encrypt(stp->str_output, b, stp->str_sched, 1); |
| 606 | bcopy((void *)b, (void *)stp->str_feed, sizeof(Block)); |
| 607 | index = 0; |
| 608 | } |
| 609 | |
| 610 | /* On encryption, we store (feed ^ data) which is cypher */ |
| 611 | *s = stp->str_output[index] = (stp->str_feed[index] ^ *s); |
| 612 | s++; |
| 613 | index++; |
| 614 | } |
| 615 | stp->str_index = index; |
| 616 | } |
| 617 | |
| 618 | int |
| 619 | cfb64_decrypt(data) |
| 620 | int data; |
| 621 | { |
| 622 | register struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1]; |
| 623 | int index; |
| 624 | |
| 625 | if (data == -1) { |
| 626 | /* |
| 627 | * Back up one byte. It is assumed that we will |
| 628 | * never back up more than one byte. If we do, this |
| 629 | * may or may not work. |
| 630 | */ |
| 631 | if (stp->str_index) |
| 632 | --stp->str_index; |
| 633 | return(0); |
| 634 | } |
| 635 | |
| 636 | index = stp->str_index++; |
| 637 | if (index == sizeof(Block)) { |
| 638 | Block b; |
| 639 | des_ecb_encrypt(stp->str_output, b, stp->str_sched, 1); |
| 640 | bcopy((void *)b, (void *)stp->str_feed, sizeof(Block)); |
| 641 | stp->str_index = 1; /* Next time will be 1 */ |
| 642 | index = 0; /* But now use 0 */ |
| 643 | } |
| 644 | |
| 645 | /* On decryption we store (data) which is cypher. */ |
| 646 | stp->str_output[index] = data; |
| 647 | return(data ^ stp->str_feed[index]); |
| 648 | } |
| 649 | |
| 650 | /* |
| 651 | * DES 64 bit Output Feedback |
| 652 | * |
| 653 | * key --->+-----+ |
| 654 | * +->| DES |--+ |
| 655 | * | +-----+ | |
| 656 | * +-----------+ |
| 657 | * v |
| 658 | * INPUT -------->(+) ----> DATA |
| 659 | * |
| 660 | * Given: |
| 661 | * iV: Initial vector, 64 bits (8 bytes) long. |
| 662 | * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). |
| 663 | * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. |
| 664 | * |
| 665 | * V0 = DES(iV, key) |
| 666 | * V(n+1) = DES(Vn, key) |
| 667 | * On = Dn ^ Vn |
| 668 | */ |
| 669 | void |
| 670 | ofb64_encrypt(s, c) |
| 671 | register unsigned char *s; |
| 672 | int c; |
| 673 | { |
| 674 | register struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1]; |
| 675 | register int index; |
| 676 | |
| 677 | index = stp->str_index; |
| 678 | while (c-- > 0) { |
| 679 | if (index == sizeof(Block)) { |
| 680 | Block b; |
| 681 | des_ecb_encrypt(stp->str_feed, b, stp->str_sched, 1); |
| 682 | bcopy((void *)b, (void *)stp->str_feed, sizeof(Block)); |
| 683 | index = 0; |
| 684 | } |
| 685 | *s++ ^= stp->str_feed[index]; |
| 686 | index++; |
| 687 | } |
| 688 | stp->str_index = index; |
| 689 | } |
| 690 | |
| 691 | int |
| 692 | ofb64_decrypt(data) |
| 693 | int data; |
| 694 | { |
| 695 | register struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1]; |
| 696 | int index; |
| 697 | |
| 698 | if (data == -1) { |
| 699 | /* |
| 700 | * Back up one byte. It is assumed that we will |
| 701 | * never back up more than one byte. If we do, this |
| 702 | * may or may not work. |
| 703 | */ |
| 704 | if (stp->str_index) |
| 705 | --stp->str_index; |
| 706 | return(0); |
| 707 | } |
| 708 | |
| 709 | index = stp->str_index++; |
| 710 | if (index == sizeof(Block)) { |
| 711 | Block b; |
| 712 | des_ecb_encrypt(stp->str_feed, b, stp->str_sched, 1); |
| 713 | bcopy((void *)b, (void *)stp->str_feed, sizeof(Block)); |
| 714 | stp->str_index = 1; /* Next time will be 1 */ |
| 715 | index = 0; /* But now use 0 */ |
| 716 | } |
| 717 | |
| 718 | return(data ^ stp->str_feed[index]); |
| 719 | } |
| 720 | #endif |