git.distorted.org.uk Git - u/mdw/catacomb/blob - catcrypt.c

   1 /* -*-c-*-
   2  *
   3  * $Id: catcrypt.c,v 1.2 2004/05/09 13:03:46 mdw Exp $
   4  *
   5  * Command-line encryption tool
   6  *
   7  * (c) 2004 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 /*----- Header files ------------------------------------------------------*/
  31
  32 #include "config.h"
  33
  34 #include <errno.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #include <mLib/base64.h>
  40 #include <mLib/dstr.h>
  41 #include <mLib/mdwopt.h>
  42 #include <mLib/quis.h>
  43 #include <mLib/report.h>
  44 #include <mLib/sub.h>
  45
  46 #include "buf.h"
  47 #include "rand.h"
  48 #include "noise.h"
  49 #include "mprand.h"
  50 #include "key.h"
  51 #include "cc.h"
  52
  53 /*----- Utilities ---------------------------------------------------------*/
  54
  55 /* --- @keyreport@ --- *
  56  *
  57  * Arguments:   @const char *file@ = filename containing the error
  58  *              @int line@ = line number in file
  59  *              @const char *err@ = error text message
  60  *              @void *p@ = unimportant pointer
  61  *
  62  * Returns:     ---
  63  *
  64  * Use:         Reports errors during the opening of a key file.
  65  */
  66
  67 static void keyreport(const char *file, int line, const char *err, void *p)
  68 {
  69   moan("error in keyring `%s' at line `%s': %s", file, line, err);
  70 }
  71
  72 /*----- Static variables --------------------------------------------------*/
  73
  74 static const char *keyring = "keyring";
  75
  76 /*----- Data format -------------------------------------------------------*/
  77
  78 /* --- Overview --- *
  79  *
  80  * The encrypted message is divided into chunks, each preceded by a two-octet
  81  * length.  The chunks don't need to be large -- the idea is that we can
  82  * stream the chunks in and out.
  83  *
  84  * The first chunk is a header.  It contains the decryption key-id, and maybe
  85  * the verification key-id if the message is signed.
  86  *
  87  * Next comes the key-encapsulation chunk.  This is decrypted in some
  88  * KEM-specific way to yield a secret hash.  This hash is what is signed if
  89  * the message is signed.  The hash is expanded using an MGF (or similar) to
  90  * make a symmetric encryption and MAC key.
  91  *
  92  * If the message is signed, there comes a signature chunk.  The signature is
  93  * on the secret hash.  This means that the recipient can modify the message
  94  * and still have a valid signature, so it's not useful for proving things to
  95  * other people; but it also means that the recipient knows that the message
  96  * is from someone who knows the hash, which limits the possiblities to (a)
  97  * whoever encrypted the message (good!) and (b) whoever knows the
  98  * recipient's private key.
  99  *
 100  * Then come message chunks.  Each one begins with a MAC over an implicit
 101  * sequence number and the ciphertext.  The final chunk's ciphertext is
 102  * empty; no other chunk is empty.  Thus can the correct end-of-file be
 103  * discerned.
 104  */
 105
 106 /*----- Chunk I/O ---------------------------------------------------------*/
 107
 108 static void chunk_write(enc *e, buf *b)
 109 {
 110   octet l[2];
 111   size_t n = BLEN(b);
 112   assert(n <= MASK16);
 113   STORE16(l, n);
 114   if (e->ops->write(e, l, 2) ||
 115       e->ops->write(e, BBASE(b), BLEN(b)))
 116     die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 117 }
 118
 119 static void chunk_read(enc *e, dstr *d, buf *b)
 120 {
 121   octet l[2];
 122   size_t n;
 123
 124   dstr_reset(d);
 125   errno = 0;
 126   if (e->ops->read(e, l, 2) != 2)
 127     goto err;
 128   n = LOAD16(l);
 129   dstr_ensure(d, n);
 130   if (e->ops->read(e, d->buf, n) != n)
 131     goto err;
 132   d->len = n;
 133   buf_init(b, d->buf, d->len);
 134   return;
 135
 136 err:
 137   if (!errno) die(EXIT_FAILURE, "unexpected end-of-file on input");
 138   else die(EXIT_FAILURE, "error reading input: %s", strerror(errno));
 139 }
 140
 141 /*----- Encryption --------------------------------------------------------*/
 142
 143 static int encrypt(int argc, char *argv[])
 144 {
 145   const char *of = 0, *kn = "ccrypt";
 146   FILE *ofp = 0;
 147   FILE *fp = 0;
 148   const char *ef = "binary";
 149   const char *err;
 150   int i;
 151   size_t n;
 152   dstr d = DSTR_INIT;
 153   octet *tag, *ct;
 154   buf b;
 155   size_t seq;
 156   char bb[16384];
 157   unsigned f = 0;
 158   key_file kf;
 159   key *k;
 160   kem *km;
 161   gcipher *cx, *c;
 162   gmac *m;
 163   ghash *h;
 164   const encops *eo;
 165   enc *e;
 166
 167 #define f_bogus 1u
 168
 169   for (;;) {
 170     static const struct option opt[] = {
 171       { "key",          OPTF_ARGREQ,    0,      'k' },
 172       { "armour",       0,              0,      'a' },
 173       { "armor",        0,              0,      'a' },
 174       { "format",       OPTF_ARGREQ,    0,      'f' },
 175       { "output",       OPTF_ARGREQ,    0,      'o' },
 176       { 0,              0,              0,      0 }
 177     };
 178     i = mdwopt(argc, argv, "k:af:o:", opt, 0, 0, 0);
 179     if (i < 0) break;
 180     switch (i) {
 181       case 'k': kn = optarg; break;
 182       case 'a': ef = "pem"; break;
 183       case 'f': ef = optarg; break;
 184       case 'o': of = optarg; break;
 185       default: f |= f_bogus; break;
 186     }
 187   }
 188   if (argc - optind > 1 || (f & f_bogus))
 189     die(EXIT_FAILURE, "Usage: encrypt [-options] [file]");
 190
 191   if (key_open(&kf, keyring, KOPEN_READ, keyreport, 0))
 192     die(EXIT_FAILURE, "can't open keyring `%s'", keyring);
 193   if ((k = key_bytag(&kf, kn)) == 0)
 194     die(EXIT_FAILURE, "key `%s' not found", kn);
 195
 196   if ((eo = getenc(ef)) == 0)
 197     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 198
 199   if (optind == argc)
 200     fp = stdin;
 201   else if (strcmp(argv[optind], "-") == 0) {
 202     fp = stdin;
 203     optind++;
 204   } else if ((fp = fopen(argv[optind], "rb")) == 0) {
 205     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 206         argv[optind], strerror(errno));
 207   } else
 208     optind++;
 209
 210   if (!of || strcmp(of, "-") == 0)
 211     ofp = stdout;
 212   else if ((ofp = fopen(of, eo->wmode)) == 0) {
 213     die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 214         ofp, strerror(errno));
 215   }
 216
 217   key_fulltag(k, &d);
 218   e = initenc(eo, ofp, "CATCRYPT ENCRYPTED MESSAGE", 1);
 219   km = getkem(k, "ccrypt", 0);
 220   if ((err = km->ops->check(km)) != 0)
 221     moan("key `%s' fails check: %s", d.buf, err);
 222
 223   /* --- Build the header chunk --- */
 224
 225   dstr_reset(&d);
 226   dstr_ensure(&d, 256);
 227   buf_init(&b, d.buf, 256);
 228   buf_putu32(&b, k->id);
 229   assert(BOK(&b));
 230   chunk_write(e, &b);
 231
 232   /* --- Build the KEM chunk --- */
 233
 234   dstr_reset(&d);
 235   if (setupkem(km, &d, &cx, &c, &m))
 236     die(EXIT_FAILURE, "failed to encapsulate key");
 237   buf_init(&b, d.buf, d.len);
 238   BSTEP(&b, d.len);
 239   chunk_write(e, &b);
 240
 241   /* --- Now do the main crypto --- */
 242
 243   assert(GC_CLASS(c)->blksz <= sizeof(bb));
 244   dstr_ensure(&d, sizeof(bb) + GM_CLASS(m)->hashsz);
 245   seq = 0;
 246   for (;;) {
 247     h = GM_INIT(m);
 248     STORE32(bb, seq);
 249     GH_HASH(h, bb, 4);
 250     seq++;
 251     if (GC_CLASS(c)->blksz) {
 252       GC_ENCRYPT(cx, 0, bb, GC_CLASS(c)->blksz);
 253       GC_SETIV(c, bb);
 254     }
 255     n = fread(bb, 1, sizeof(bb), fp);
 256     if (!n) break;
 257     buf_init(&b, d.buf, d.sz);
 258     tag = buf_get(&b, GM_CLASS(m)->hashsz);
 259     ct = buf_get(&b, n);
 260     assert(tag); assert(ct);
 261     GC_ENCRYPT(c, bb, ct, n);
 262     GH_HASH(h, ct, n);
 263     GH_DONE(h, tag);
 264     GH_DESTROY(h);
 265     chunk_write(e, &b);
 266   }
 267
 268   /* --- Final terminator packet --- */
 269
 270   buf_init(&b, d.buf, d.sz);
 271   tag = buf_get(&b, GM_CLASS(m)->hashsz);
 272   assert(tag);
 273   GH_DONE(h, tag);
 274   GH_DESTROY(h);
 275   chunk_write(e, &b);
 276
 277   /* --- All done --- */
 278
 279   e->ops->encdone(e);
 280   GM_DESTROY(m);
 281   GC_DESTROY(c);
 282   GC_DESTROY(cx);
 283   freeenc(e);
 284   freekem(km);
 285   if (of) fclose(ofp);
 286   key_close(&kf);
 287   dstr_destroy(&d);
 288   return (0);
 289
 290 #undef f_bogus
 291 }
 292
 293 /*---- Decryption ---------------------------------------------------------*/
 294
 295 static int decrypt(int argc, char *argv[])
 296 {
 297   const char *of = 0;
 298   FILE *ofp = 0;
 299   FILE *fp = 0;
 300   const char *ef = "binary";
 301   int i;
 302   dstr d = DSTR_INIT;
 303   buf b;
 304   key_file kf;
 305   size_t seq;
 306   uint32 id;
 307   key *k;
 308   kem *km;
 309   gcipher *cx;
 310   gcipher *c;
 311   ghash *h;
 312   gmac *m;
 313   octet *tag;
 314   unsigned f = 0;
 315   const encops *eo;
 316   enc *e;
 317
 318 #define f_bogus 1u
 319
 320   for (;;) {
 321     static const struct option opt[] = {
 322       { "armour",       0,              0,      'a' },
 323       { "armor",        0,              0,      'a' },
 324       { "format",       OPTF_ARGREQ,    0,      'f' },
 325       { "output",       OPTF_ARGREQ,    0,      'o' },
 326       { 0,              0,              0,      0 }
 327     };
 328     i = mdwopt(argc, argv, "af:o:", opt, 0, 0, 0);
 329     if (i < 0) break;
 330     switch (i) {
 331       case 'a': ef = "pem"; break;
 332       case 'f': ef = optarg; break;
 333       case 'o': of = optarg; break;
 334       default: f |= f_bogus; break;
 335     }
 336   }
 337   if (argc - optind > 1 || (f & f_bogus))
 338     die(EXIT_FAILURE, "Usage: decrypt [-options] [file]");
 339
 340   if ((eo = getenc(ef)) == 0)
 341     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 342
 343   if (optind == argc)
 344     fp = stdin;
 345   else if (strcmp(argv[optind], "-") == 0) {
 346     fp = stdin;
 347     optind++;
 348   } else if ((fp = fopen(argv[optind], eo->rmode)) == 0) {
 349     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 350         argv[optind], strerror(errno));
 351   } else
 352     optind++;
 353
 354   if (key_open(&kf, keyring, KOPEN_READ, keyreport, 0))
 355     die(EXIT_FAILURE, "can't open keyring `%s'", keyring);
 356
 357   e = initenc(eo, fp, "CATCRYPT ENCRYPTED MESSAGE", 0);
 358
 359   /* --- Read the header chunk --- */
 360
 361   chunk_read(e, &d, &b);
 362   if (buf_getu32(&b, &id))
 363     die(EXIT_FAILURE, "malformed header: missing keyid");
 364   if (BLEFT(&b))
 365     die(EXIT_FAILURE, "malformed header: junk at end");
 366
 367   /* --- Find the key --- */
 368
 369   if ((k = key_byid(&kf, id)) == 0)
 370     die(EXIT_FAILURE, "key id %08lx not found", (unsigned long)id);
 371   km = getkem(k, "ccrypt", 1);
 372
 373   /* --- Read the KEM chunk --- */
 374
 375   chunk_read(e, &d, &b);
 376   if (setupkem(km, &d, &cx, &c, &m))
 377     die(EXIT_FAILURE, "failed to decapsulate key");
 378
 379   /* --- Now decrypt the main body --- */
 380
 381   if (!of || strcmp(of, "-") == 0)
 382     ofp = stdout;
 383   else if ((ofp = fopen(of, "wb")) == 0) {
 384     die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 385         ofp, strerror(errno));
 386   }
 387
 388   seq = 0;
 389   dstr_ensure(&d, GC_CLASS(c)->blksz);
 390   dstr_ensure(&d, 4);
 391   for (;;) {
 392     if (GC_CLASS(c)->blksz) {
 393       GC_ENCRYPT(cx, 0, d.buf, GC_CLASS(c)->blksz);
 394       GC_SETIV(c, d.buf);
 395     }
 396     h = GM_INIT(m);
 397     STORE32(d.buf, seq);
 398     GH_HASH(h, d.buf, 4);
 399     seq++;
 400     chunk_read(e, &d, &b);
 401     if ((tag = buf_get(&b, GM_CLASS(m)->hashsz)) == 0)
 402       die(EXIT_FAILURE, "bad ciphertext chunk: no tag");
 403     GH_HASH(h, BCUR(&b), BLEFT(&b));
 404     if (memcmp(tag, GH_DONE(h, 0), GM_CLASS(m)->hashsz) != 0)
 405       die(EXIT_FAILURE, "bad ciphertext chunk: authentication failure");
 406     if (!BLEFT(&b))
 407       break;
 408     GC_DECRYPT(c, BCUR(&b), BCUR(&b), BLEFT(&b));
 409     if (fwrite(BCUR(&b), 1, BLEFT(&b), ofp) != BLEFT(&b))
 410       die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 411   }
 412
 413   if (fflush(ofp) || ferror(ofp))
 414     die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 415
 416   e->ops->decdone(e);
 417   freeenc(e);
 418   GC_DESTROY(c);
 419   GC_DESTROY(cx);
 420   GM_DESTROY(m);
 421   freekem(km);
 422   if (of) fclose(ofp);
 423   key_close(&kf);
 424   dstr_destroy(&d);
 425   return (0);
 426
 427 #undef f_bogus
 428 }
 429
 430 /*----- Test code ---------------------------------------------------------*/
 431
 432 static int encode(int argc, char *argv[])
 433 {
 434   const char *of = 0;
 435   FILE *ofp = 0;
 436   FILE *fp = 0;
 437   const char *ef = "binary";
 438   const char *bd = "MESSAGE";
 439   int i;
 440   size_t n;
 441   char buf[4096];
 442   unsigned f = 0;
 443   const encops *eo;
 444   enc *e;
 445
 446 #define f_bogus 1u
 447
 448   for (;;) {
 449     static const struct option opt[] = {
 450       { "format",       OPTF_ARGREQ,    0,      'f' },
 451       { "boundary",     OPTF_ARGREQ,    0,      'b' },
 452       { "output",       OPTF_ARGREQ,    0,      'o' },
 453       { 0,              0,              0,      0 }
 454     };
 455     i = mdwopt(argc, argv, "f:b:o:", opt, 0, 0, 0);
 456     if (i < 0) break;
 457     switch (i) {
 458       case 'f': ef = optarg; break;
 459       case 'b': bd = optarg; break;
 460       case 'o': of = optarg; break;
 461       default: f |= f_bogus; break;
 462     }
 463   }
 464   if (argc - optind > 1 || (f & f_bogus))
 465     die(EXIT_FAILURE, "Usage: encode [-options] [file]");
 466
 467   if ((eo = getenc(ef)) == 0)
 468     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 469
 470   if (optind == argc)
 471     fp = stdin;
 472   else if (strcmp(argv[optind], "-") == 0) {
 473     fp = stdin;
 474     optind++;
 475   } else if ((fp = fopen(argv[optind], "rb")) == 0) {
 476     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 477         argv[optind], strerror(errno));
 478   } else
 479     optind++;
 480
 481   if (!of || strcmp(of, "-") == 0)
 482     ofp = stdout;
 483   else if ((ofp = fopen(of, eo->wmode)) == 0) {
 484     die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 485         ofp, strerror(errno));
 486   }
 487
 488   e = initenc(eo, ofp, bd, 1);
 489
 490   do {
 491     n = fread(buf, 1, sizeof(buf), fp);
 492     if (e->ops->write(e, buf, n))
 493       die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 494   } while (n == sizeof(buf));
 495   e->ops->encdone(e);
 496   freeenc(e);
 497   return (0);
 498
 499 #undef f_bogus
 500 }
 501
 502 static int decode(int argc, char *argv[])
 503 {
 504   const char *of = 0;
 505   FILE *ofp = 0;
 506   FILE *fp = 0;
 507   const char *ef = "binary";
 508   const char *bd = 0;
 509   int i;
 510   char buf[4096];
 511   unsigned f = 0;
 512   const encops *eo;
 513   enc *e;
 514
 515 #define f_bogus 1u
 516
 517   for (;;) {
 518     static const struct option opt[] = {
 519       { "format",       OPTF_ARGREQ,    0,      'f' },
 520       { "boundary",     OPTF_ARGREQ,    0,      'b' },
 521       { "output",       OPTF_ARGREQ,    0,      'o' },
 522       { 0,              0,              0,      0 }
 523     };
 524     i = mdwopt(argc, argv, "f:b:o:", opt, 0, 0, 0);
 525     if (i < 0) break;
 526     switch (i) {
 527       case 'f': ef = optarg; break;
 528       case 'b': bd = optarg; break;
 529       case 'o': of = optarg; break;
 530       default: f |= f_bogus; break;
 531     }
 532   }
 533   if (argc - optind > 1 || (f & f_bogus))
 534     die(EXIT_FAILURE, "Usage: decode [-options] [file]");
 535
 536   if ((eo = getenc(ef)) == 0)
 537     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 538
 539   if (optind == argc)
 540     fp = stdin;
 541   else if (strcmp(argv[optind], "-") == 0) {
 542     fp = stdin;
 543     optind++;
 544   } else if ((fp = fopen(argv[optind], eo->rmode)) == 0) {
 545     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 546         argv[optind], strerror(errno));
 547   } else
 548     optind++;
 549
 550   if (!of || strcmp(of, "-") == 0)
 551     ofp = stdout;
 552   else if ((ofp = fopen(of, "wb")) == 0) {
 553     die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 554         ofp, strerror(errno));
 555   }
 556
 557   e = initenc(eo, fp, bd, 0);
 558
 559   do {
 560     if ((i = e->ops->read(e, buf, sizeof(buf))) < 0)
 561       die(EXIT_FAILURE, "error reading input: %s", strerror(errno));
 562     if (fwrite(buf, 1, i, ofp) < i)
 563       die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 564   } while (i == sizeof(buf));
 565   e->ops->decdone(e);
 566   freeenc(e);
 567   return (0);
 568
 569 #undef f_bogus
 570 }
 571
 572 /*----- Main code ---------------------------------------------------------*/
 573
 574 typedef struct cmd {
 575   const char *name;
 576   int (*func)(int /*argc*/, char */*argv*/[]);
 577   const char *usage;
 578   const char *help;
 579 } cmd;
 580
 581 static cmd cmdtab[] = {
 582   { "encode", encode,
 583     "encode [-f format] [-b label] [-o output] [file]",
 584     "\
 585 Options:\n\
 586 \n\
 587 -f, --format=FORMAT     Encode to FORMAT.\n\
 588 -b, --boundary=LABEL    PEM boundary is LABEL.\n\
 589 -o, --output=FILE       Write output to FILE.\n\
 590 " },
 591   { "decode", decode,
 592     "decode [-f format] [-b label] [-o output] [file]",
 593     "\
 594 Options:\n\
 595 \n\
 596 -f, --format=FORMAT     Decode from FORMAT.\n\
 597 -b, --boundary=LABEL    PEM boundary is LABEL.\n\
 598 -o, --output=FILE       Write output to FILE.\n\
 599 " },
 600   { "encrypt", encrypt,
 601     "encrypt [-a] [-k tag] [f format]] [-o output] [file]",
 602     "\
 603 Options:\n\
 604 \n\
 605 -a, --armour            Same as `-f pem'.\n\
 606 -f, --format=FORMAT     Encode as FORMAT.\n\
 607 -k, --key=TAG           Use public key named by TAG.\n\
 608 -o, --output=FILE       Write output to FILE.\n\
 609 " },
 610   { "decrypt", decrypt,
 611     "decrypt [-t] [-o output] [file]", "\
 612 Options:\n\
 613 \n\
 614 -t, --text              Read PEM-encoded input.\n\
 615 -o, --output=FILE       Write output to FILE.\n\
 616 " },
 617   { 0, 0, 0 }
 618 };
 619
 620 /* --- @findcmd@ --- *
 621  *
 622  * Arguments:   @const char *name@ = a command name
 623  *
 624  * Returns:     Pointer to the command structure.
 625  *
 626  * Use:         Looks up a command by name.  If the command isn't found, an
 627  *              error is reported and the program is terminated.
 628  */
 629
 630 static cmd *findcmd(const char *name)
 631 {
 632   cmd *c, *chosen = 0;
 633   size_t sz = strlen(name);
 634
 635   for (c = cmdtab; c->name; c++) {
 636     if (strncmp(name, c->name, sz) == 0) {
 637       if (c->name[sz] == 0) {
 638         chosen = c;
 639         break;
 640       } else if (chosen)
 641         die(EXIT_FAILURE, "ambiguous command name `%s'", name);
 642       else
 643         chosen = c;
 644     }
 645   }
 646   if (!chosen)
 647     die(EXIT_FAILURE, "unknown command name `%s'", name);
 648   return (chosen);
 649 }
 650
 651 static void version(FILE *fp)
 652 {
 653   pquis(fp, "$, Catacomb version " VERSION "\n");
 654 }
 655
 656 static void usage(FILE *fp)
 657 {
 658   pquis(fp, "Usage: $ [-k keyring] command [args]\n");
 659 }
 660
 661 static void help(FILE *fp, char **argv)
 662 {
 663   cmd *c;
 664
 665   if (*argv) {
 666     c = findcmd(*argv);
 667     fprintf(fp, "Usage: %s [-k keyring] %s\n", QUIS, c->usage);
 668     if (c->help) {
 669       fputc('\n', fp);
 670       fputs(c->help, fp);
 671     }
 672   } else {
 673     version(fp);
 674     fputc('\n', fp);
 675     usage(fp);
 676     fputs("\n\
 677 Encrypt and decrypt files.\n\
 678 \n", fp);
 679     for (c = cmdtab; c->name; c++)
 680       fprintf(fp, "%s\n", c->usage);
 681   }
 682 }
 683
 684 /* --- @main@ --- *
 685  *
 686  * Arguments:   @int argc@ = number of command line arguments
 687  *              @char *argv[]@ = vector of command line arguments
 688  *
 689  * Returns:     Zero if successful, nonzero otherwise.
 690  *
 691  * Use:         Signs or verifies signatures on lists of files.  Useful for
 692  *              ensuring that a distribution is unmolested.
 693  */
 694
 695 int main(int argc, char *argv[])
 696 {
 697   unsigned f = 0;
 698
 699 #define f_bogus 1u
 700
 701   /* --- Initialize the library --- */
 702
 703   ego(argv[0]);
 704   sub_init();
 705   rand_noisesrc(RAND_GLOBAL, &noise_source);
 706   rand_seed(RAND_GLOBAL, 160);
 707
 708   /* --- Parse options --- */
 709
 710   for (;;) {
 711     static struct option opts[] = {
 712       { "help",         0,              0,      'h' },
 713       { "version",      0,              0,      'v' },
 714       { "usage",        0,              0,      'u' },
 715       { "keyring",      OPTF_ARGREQ,    0,      'k' },
 716       { 0,              0,              0,      0 }
 717     };
 718     int i = mdwopt(argc, argv, "+hvu k:", opts, 0, 0, 0);
 719     if (i < 0)
 720       break;
 721     switch (i) {
 722       case 'h':
 723         help(stdout, argv + optind);
 724         exit(0);
 725         break;
 726       case 'v':
 727         version(stdout);
 728         exit(0);
 729         break;
 730       case 'u':
 731         usage(stdout);
 732         exit(0);
 733       case 'k':
 734         keyring = optarg;
 735         break;
 736       default:
 737         f |= f_bogus;
 738         break;
 739     }
 740   }
 741
 742   argc -= optind;
 743   argv += optind;
 744   optind = 0;
 745   if (f & f_bogus || argc < 1) {
 746     usage(stderr);
 747     exit(EXIT_FAILURE);
 748   }
 749
 750   /* --- Dispatch to the correct subcommand handler --- */
 751
 752   return (findcmd(argv[0])->func(argc, argv));
 753
 754 #undef f_bogus
 755 }
 756
 757 /*----- That's all, folks -------------------------------------------------*/