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

   1 /* -*-c-*-
   2  *
   3  * $Id$
   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 #include "ectab.h"
  54 #include "ptab.h"
  55
  56 /*----- Utilities ---------------------------------------------------------*/
  57
  58 /* --- @keyreport@ --- *
  59  *
  60  * Arguments:   @const char *file@ = filename containing the error
  61  *              @int line@ = line number in file
  62  *              @const char *err@ = error text message
  63  *              @void *p@ = unimportant pointer
  64  *
  65  * Returns:     ---
  66  *
  67  * Use:         Reports errors during the opening of a key file.
  68  */
  69
  70 static void keyreport(const char *file, int line, const char *err, void *p)
  71 {
  72   moan("error in keyring `%s' at line `%s': %s", file, line, err);
  73 }
  74
  75 /*----- Static variables --------------------------------------------------*/
  76
  77 static const char *keyring = "keyring";
  78
  79 /*----- Data format -------------------------------------------------------*/
  80
  81 /* --- Overview --- *
  82  *
  83  * The encrypted message is divided into chunks, each preceded by a two-octet
  84  * length.  The chunks don't need to be large -- the idea is that we can
  85  * stream the chunks in and out.
  86  *
  87  * The first chunk is a header.  It contains the decryption key-id, and maybe
  88  * the verification key-id if the message is signed.
  89  *
  90  * Next comes the key-encapsulation chunk.  This is decrypted in some
  91  * KEM-specific way to yield a secret hash.  The hash is expanded using an
  92  * MGF (or similar) to make a symmetric encryption and MAC key.
  93  *
  94  * If the message is signed, there comes a signature chunk.  The signature is
  95  * on the further output of the MGF.  This means that the recipient can
  96  * modify the message and still have a valid signature, so it's not useful
  97  * for proving things to other people; but it also means that the recipient
  98  * knows that the message is from someone who knows the hash, which limits
  99  * the possiblities to (a) whoever encrypted the message (good!) and (b)
 100  * whoever knows the recipient's private key.
 101  *
 102  * Then come message chunks.  Each one begins with a MAC over an implicit
 103  * sequence number and the ciphertext.  The final chunk's ciphertext is
 104  * empty; no other chunk is empty.  Thus can the correct end-of-file be
 105  * discerned.
 106  */
 107
 108 /*----- Chunk I/O ---------------------------------------------------------*/
 109
 110 static void chunk_write(enc *e, buf *b)
 111 {
 112   octet l[2];
 113   size_t n = BLEN(b);
 114   assert(n <= MASK16);
 115   STORE16(l, n);
 116   if (e->ops->write(e, l, 2) ||
 117       e->ops->write(e, BBASE(b), BLEN(b)))
 118     die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 119 }
 120
 121 static void chunk_read(enc *e, dstr *d, buf *b)
 122 {
 123   octet l[2];
 124   size_t n;
 125
 126   dstr_reset(d);
 127   errno = 0;
 128   if (e->ops->read(e, l, 2) != 2)
 129     goto err;
 130   n = LOAD16(l);
 131   dstr_ensure(d, n);
 132   if (e->ops->read(e, d->buf, n) != n)
 133     goto err;
 134   d->len = n;
 135   buf_init(b, d->buf, d->len);
 136   return;
 137
 138 err:
 139   if (!errno) die(EXIT_FAILURE, "unexpected end-of-file on input");
 140   else die(EXIT_FAILURE, "error reading input: %s", strerror(errno));
 141 }
 142
 143 /*----- Encryption --------------------------------------------------------*/
 144
 145 static int encrypt(int argc, char *argv[])
 146 {
 147   const char *of = 0, *kn = "ccrypt", *skn = 0;
 148   FILE *ofp = 0;
 149   FILE *fp = 0;
 150   const char *ef = "binary";
 151   const char *err;
 152   int i;
 153   int en;
 154   size_t n;
 155   dstr d = DSTR_INIT;
 156   octet *tag, *ct;
 157   buf b;
 158   size_t seq;
 159   char bb[16384];
 160   unsigned f = 0;
 161   key_file kf;
 162   key *k;
 163   key *sk = 0;
 164   kem *km;
 165   sig *s = 0;
 166   gcipher *cx, *c;
 167   gmac *m;
 168   ghash *h;
 169   const encops *eo;
 170   enc *e;
 171
 172 #define f_bogus 1u
 173
 174   for (;;) {
 175     static const struct option opt[] = {
 176       { "key",          OPTF_ARGREQ,    0,      'k' },
 177       { "sign-key",     OPTF_ARGREQ,    0,      's' },
 178       { "armour",       0,              0,      'a' },
 179       { "armor",        0,              0,      'a' },
 180       { "format",       OPTF_ARGREQ,    0,      'f' },
 181       { "output",       OPTF_ARGREQ,    0,      'o' },
 182       { 0,              0,              0,      0 }
 183     };
 184     i = mdwopt(argc, argv, "k:s:af:o:", opt, 0, 0, 0);
 185     if (i < 0) break;
 186     switch (i) {
 187       case 'k': kn = optarg; break;
 188       case 's': skn = optarg; break;
 189       case 'a': ef = "pem"; break;
 190       case 'f': ef = optarg; break;
 191       case 'o': of = optarg; break;
 192       default: f |= f_bogus; break;
 193     }
 194   }
 195   if (argc - optind > 1 || (f & f_bogus))
 196     die(EXIT_FAILURE, "Usage: encrypt [-OPTIONS] [FILE]");
 197
 198   if (key_open(&kf, keyring, KOPEN_READ, keyreport, 0))
 199     die(EXIT_FAILURE, "can't open keyring `%s'", keyring);
 200   if ((k = key_bytag(&kf, kn)) == 0)
 201     die(EXIT_FAILURE, "key `%s' not found", kn);
 202   if (skn && (sk = key_bytag(&kf, skn)) == 0)
 203     die(EXIT_FAILURE, "key `%s' not found", skn);
 204
 205   if ((eo = getenc(ef)) == 0)
 206     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 207
 208   if (optind == argc)
 209     fp = stdin;
 210   else if (strcmp(argv[optind], "-") == 0) {
 211     fp = stdin;
 212     optind++;
 213   } else if ((fp = fopen(argv[optind], "rb")) == 0) {
 214     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 215         argv[optind], strerror(errno));
 216   } else
 217     optind++;
 218
 219   if (!of || strcmp(of, "-") == 0)
 220     ofp = stdout;
 221   else if ((ofp = fopen(of, eo->wmode)) == 0) {
 222     die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 223         ofp, strerror(errno));
 224   }
 225
 226   dstr_reset(&d);
 227   key_fulltag(k, &d);
 228   e = initenc(eo, ofp, "CATCRYPT ENCRYPTED MESSAGE");
 229   km = getkem(k, "cckem", 0);
 230   if ((err = km->ops->check(km)) != 0)
 231     moan("key %s fails check: %s", d.buf, err);
 232   if (sk) {
 233     dstr_reset(&d);
 234     key_fulltag(sk, &d);
 235     s = getsig(sk, "ccsig", 1);
 236     if ((err = s->ops->check(s)) != 0)
 237       moan("key %s fails check: %s", d.buf, err);
 238   }
 239
 240   /* --- Build the header chunk --- */
 241
 242   dstr_reset(&d);
 243   dstr_ensure(&d, 256);
 244   buf_init(&b, d.buf, 256);
 245   buf_putu32(&b, k->id);
 246   if (sk) buf_putu32(&b, sk->id);
 247   assert(BOK(&b));
 248   chunk_write(e, &b);
 249
 250   /* --- Build the KEM chunk --- */
 251
 252   dstr_reset(&d);
 253   if (setupkem(km, &d, &cx, &c, &m))
 254     die(EXIT_FAILURE, "failed to encapsulate key");
 255   buf_init(&b, d.buf, d.len);
 256   BSTEP(&b, d.len);
 257   chunk_write(e, &b);
 258
 259   /* --- Write the signature chunk --- */
 260
 261   if (s) {
 262     GC_ENCRYPT(cx, 0, bb, 1024);
 263     GH_HASH(s->h, bb, 1024);
 264     dstr_reset(&d);
 265     if ((en = s->ops->doit(s, &d)) != 0)
 266       die(EXIT_FAILURE, "error creating signature: %s", key_strerror(en));
 267     buf_init(&b, d.buf, d.len);
 268     BSTEP(&b, d.len);
 269     chunk_write(e, &b);
 270   }
 271
 272   /* --- Now do the main crypto --- */
 273
 274   assert(GC_CLASS(c)->blksz <= sizeof(bb));
 275   dstr_ensure(&d, sizeof(bb) + GM_CLASS(m)->hashsz);
 276   seq = 0;
 277   for (;;) {
 278     h = GM_INIT(m);
 279     GH_HASHU32(h, seq);
 280     seq++;
 281     if (GC_CLASS(c)->blksz) {
 282       GC_ENCRYPT(cx, 0, bb, GC_CLASS(c)->blksz);
 283       GC_SETIV(c, bb);
 284     }
 285     n = fread(bb, 1, sizeof(bb), fp);
 286     if (!n) break;
 287     buf_init(&b, d.buf, d.sz);
 288     tag = buf_get(&b, GM_CLASS(m)->hashsz);
 289     ct = buf_get(&b, n);
 290     assert(tag); assert(ct);
 291     GC_ENCRYPT(c, bb, ct, n);
 292     GH_HASH(h, ct, n);
 293     GH_DONE(h, tag);
 294     GH_DESTROY(h);
 295     chunk_write(e, &b);
 296   }
 297
 298   /* --- Final terminator packet --- */
 299
 300   buf_init(&b, d.buf, d.sz);
 301   tag = buf_get(&b, GM_CLASS(m)->hashsz);
 302   assert(tag);
 303   GH_DONE(h, tag);
 304   GH_DESTROY(h);
 305   chunk_write(e, &b);
 306
 307   /* --- All done --- */
 308
 309   e->ops->encdone(e);
 310   GM_DESTROY(m);
 311   GC_DESTROY(c);
 312   GC_DESTROY(cx);
 313   freeenc(e);
 314   if (s) freesig(s);
 315   freekem(km);
 316   if (of) fclose(ofp);
 317   key_close(&kf);
 318   dstr_destroy(&d);
 319   return (0);
 320
 321 #undef f_bogus
 322 }
 323
 324 /*---- Decryption ---------------------------------------------------------*/
 325
 326 static int decrypt(int argc, char *argv[])
 327 {
 328   const char *of = 0;
 329   FILE *ofp = 0, *rfp = 0;
 330   FILE *fp = 0;
 331   const char *ef = "binary";
 332   int i;
 333   size_t n;
 334   dstr d = DSTR_INIT;
 335   buf b;
 336   key_file kf;
 337   size_t seq;
 338   uint32 id;
 339   key *k;
 340   key *sk = 0;
 341   kem *km;
 342   sig *s = 0;
 343   gcipher *cx;
 344   gcipher *c;
 345   ghash *h;
 346   gmac *m;
 347   octet *tag;
 348   unsigned f = 0;
 349   const encops *eo;
 350   const char *err;
 351   int verb = 1;
 352   enc *e;
 353
 354 #define f_bogus 1u
 355 #define f_buffer 2u
 356
 357   for (;;) {
 358     static const struct option opt[] = {
 359       { "armour",       0,              0,      'a' },
 360       { "armor",        0,              0,      'a' },
 361       { "buffer",       0,              0,      'b' },
 362       { "verbose",      0,              0,      'v' },
 363       { "quiet",        0,              0,      'q' },
 364       { "format",       OPTF_ARGREQ,    0,      'f' },
 365       { "output",       OPTF_ARGREQ,    0,      'o' },
 366       { 0,              0,              0,      0 }
 367     };
 368     i = mdwopt(argc, argv, "abf:o:qv", opt, 0, 0, 0);
 369     if (i < 0) break;
 370     switch (i) {
 371       case 'a': ef = "pem"; break;
 372       case 'b': f |= f_buffer; break;
 373       case 'v': verb++; break;
 374       case 'q': if (verb) verb--; break;
 375       case 'f': ef = optarg; break;
 376       case 'o': of = optarg; break;
 377       default: f |= f_bogus; break;
 378     }
 379   }
 380   if (argc - optind > 1 || (f & f_bogus))
 381     die(EXIT_FAILURE, "Usage: decrypt [-OPTIONS] [FILE]");
 382
 383   if ((eo = getenc(ef)) == 0)
 384     die(EXIT_FAILURE, "encoding `%s' not found", ef);
 385
 386   if (optind == argc)
 387     fp = stdin;
 388   else if (strcmp(argv[optind], "-") == 0) {
 389     fp = stdin;
 390     optind++;
 391   } else if ((fp = fopen(argv[optind], eo->rmode)) == 0) {
 392     die(EXIT_FAILURE, "couldn't open file `%s': %s",
 393         argv[optind], strerror(errno));
 394   } else
 395     optind++;
 396
 397   if (key_open(&kf, keyring, KOPEN_READ, keyreport, 0))
 398     die(EXIT_FAILURE, "can't open keyring `%s'", keyring);
 399
 400   e = initdec(eo, fp, checkbdry, "CATCRYPT ENCRYPTED MESSAGE");
 401
 402   /* --- Read the header chunk --- */
 403
 404   chunk_read(e, &d, &b);
 405   if (buf_getu32(&b, &id)) {
 406     if (verb) printf("FAIL malformed header: missing keyid\n");
 407     exit(EXIT_FAILURE);
 408   }
 409   if ((k = key_byid(&kf, id)) == 0) {
 410     if (verb) printf("FAIL key id %08lx not found\n", (unsigned long)id);
 411     exit(EXIT_FAILURE);
 412   }
 413   if (BLEFT(&b)) {
 414     if (buf_getu32(&b, &id)) {
 415       if (verb) printf("FAIL malformed header: missing signature keyid\n");
 416       exit(EXIT_FAILURE);
 417     }
 418     if ((sk = key_byid(&kf, id)) == 0) {
 419       if (verb) printf("FAIL key id %08lx not found\n", (unsigned long)id);
 420       exit(EXIT_FAILURE);
 421     }
 422   }
 423   if (BLEFT(&b)) {
 424     if (verb) printf("FAIL malformed header: junk at end\n");
 425     exit(EXIT_FAILURE);
 426   }
 427
 428   /* --- Find the key --- */
 429
 430   km = getkem(k, "cckem", 1);
 431
 432   /* --- Read the KEM chunk --- */
 433
 434   chunk_read(e, &d, &b);
 435   if (setupkem(km, &d, &cx, &c, &m)) {
 436     if (verb) printf("FAIL failed to decapsulate key\n");
 437     exit(EXIT_FAILURE);
 438   }
 439
 440   /* --- Verify the signature, if there is one --- */
 441
 442   if (sk) {
 443     s = getsig(sk, "ccsig", 0);
 444     dstr_reset(&d);
 445     key_fulltag(sk, &d);
 446     if (verb && (err = s->ops->check(s)) != 0)
 447       printf("WARN verification key %s fails check: %s\n", d.buf, err);
 448     dstr_reset(&d);
 449     dstr_ensure(&d, 1024);
 450     GC_ENCRYPT(cx, 0, d.buf, 1024);
 451     GH_HASH(s->h, d.buf, 1024);
 452     chunk_read(e, &d, &b);
 453     if (s->ops->doit(s, &d)) {
 454       if (verb) printf("FAIL signature verification failed\n");
 455       exit(EXIT_FAILURE);
 456     }
 457     if (verb) {
 458       dstr_reset(&d);
 459       key_fulltag(sk, &d);
 460       printf("INFO good-signature %s\n", d.buf);
 461     }
 462   } else if (verb)
 463     printf("INFO no-signature\n");
 464
 465   /* --- Now decrypt the main body --- */
 466
 467   if (!of || strcmp(of, "-") == 0) {
 468     ofp = stdout;
 469     f |= f_buffer;
 470   }
 471   if (!(f & f_buffer)) {
 472     if ((ofp = fopen(of, "wb")) == 0) {
 473       die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 474           ofp, strerror(errno));
 475     }
 476     rfp = ofp;
 477   } else if ((rfp = tmpfile()) == 0)
 478     die(EXIT_FAILURE, "couldn't create temporary file: %s", strerror(errno));
 479
 480   seq = 0;
 481   dstr_ensure(&d, GC_CLASS(c)->blksz);
 482   dstr_ensure(&d, 4);
 483   for (;;) {
 484     if (GC_CLASS(c)->blksz) {
 485       GC_ENCRYPT(cx, 0, d.buf, GC_CLASS(c)->blksz);
 486       GC_SETIV(c, d.buf);
 487     }
 488     h = GM_INIT(m);
 489     GH_HASHU32(h, seq);
 490     seq++;
 491     chunk_read(e, &d, &b);
 492     if ((tag = buf_get(&b, GM_CLASS(m)->hashsz)) == 0) {
 493       if (verb) printf("FAIL bad ciphertext chunk: no tag\n");
 494       exit(EXIT_FAILURE);
 495     }
 496     GH_HASH(h, BCUR(&b), BLEFT(&b));
 497     if (memcmp(tag, GH_DONE(h, 0), GM_CLASS(m)->hashsz) != 0) {
 498       if (verb)
 499         printf("FAIL bad ciphertext chunk: authentication failure\n");
 500       exit(EXIT_FAILURE);
 501     }
 502     if (!BLEFT(&b))
 503       break;
 504     GC_DECRYPT(c, BCUR(&b), BCUR(&b), BLEFT(&b));
 505     if (fwrite(BCUR(&b), 1, BLEFT(&b), rfp) != BLEFT(&b)) {
 506       if (verb) printf("FAIL error writing output: %s\n", strerror(errno));
 507       exit(EXIT_FAILURE);
 508     }
 509   }
 510
 511   if (fflush(rfp) || ferror(rfp)) {
 512     if (verb) printf("FAIL error writing output: %s\n", strerror(errno));
 513     exit(EXIT_FAILURE);
 514   }
 515   if (f & f_buffer) {
 516     if (!ofp && (ofp = fopen(of, "wb")) == 0) {
 517       die(EXIT_FAILURE, "couldn't open file `%s' for output: %s",
 518           of, strerror(errno));
 519     }
 520     rewind(rfp);
 521     dstr_reset(&d);
 522     dstr_ensure(&d, 65536);
 523     if (verb && ofp == stdout) printf("DATA\n");
 524     for (;;) {
 525       n = fread(d.buf, 1, d.sz, rfp);
 526       if (!n) break;
 527       if (fwrite(d.buf, 1, n, ofp) < n)
 528         die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 529     }
 530     if (ferror(rfp) || fclose(rfp))
 531       die(EXIT_FAILURE, "error unbuffering output: %s", strerror(errno));
 532   }
 533   if (ofp && (fflush(ofp) || ferror(ofp) || fclose(ofp)))
 534       die(EXIT_FAILURE, "error writing output: %s", strerror(errno));
 535
 536   e->ops->decdone(e);
 537   if (verb && ofp != stdout)
 538     printf("OK decrypted successfully\n");
 539   freeenc(e);
 540   GC_DESTROY(c);
 541   GC_DESTROY(cx);
 542   GM_DESTROY(m);
 543   freekem(km);
 544   if (of) fclose(ofp);
 545   key_close(&kf);
 546   dstr_destroy(&d);
 547   return (0);
 548
 549 #undef f_bogus
 550 #undef f_buffer
 551 }
 552
 553 /*----- Main code ---------------------------------------------------------*/
 554
 555 #define LISTS(LI)                                                       \
 556   LI("Lists", list,                                                     \
 557      listtab[i].name, listtab[i].name)                                  \
 558   LI("Key-encapsulation mechanisms", kem,                               \
 559      kemtab[i].name, kemtab[i].name)                                    \
 560   LI("Signature schemes", sig,                                          \
 561      sigtab[i].name, sigtab[i].name)                                    \
 562   LI("Encodings", enc,                                                  \
 563      enctab[i].name, enctab[i].name)                                    \
 564   LI("Symmetric encryption algorithms", cipher,                         \
 565      gciphertab[i], gciphertab[i]->name)                                \
 566   LI("Hash functions", hash,                                            \
 567      ghashtab[i], ghashtab[i]->name)                                    \
 568   LI("Message authentication codes", mac,                               \
 569      gmactab[i], gmactab[i]->name)
 570
 571 MAKELISTTAB(listtab, LISTS)
 572
 573 int cmd_show(int argc, char *argv[])
 574 {
 575   return (displaylists(listtab, argv + 1));
 576 }
 577
 578 static int cmd_help(int, char **);
 579
 580 static cmd cmdtab[] = {
 581   { "help", cmd_help, "help [COMMAND...]" },
 582   { "show", cmd_show, "show [ITEM...]" },
 583   CMD_ENCODE,
 584   CMD_DECODE,
 585   { "encrypt", encrypt,
 586     "encrypt [-a] [-k TAG] [-s TAG] [-f FORMAT]\n\t\
 587 [-o OUTPUT] [FILE]", "\
 588 Options:\n\
 589 \n\
 590 -a, --armour            Same as `-f pem'.\n\
 591 -f, --format=FORMAT     Encode as FORMAT.\n\
 592 -k, --key=TAG           Use public encryption key named by TAG.\n\
 593 -s, --sign-key=TAG      Use private signature key named by TAG.\n\
 594 -o, --output=FILE       Write output to FILE.\n\
 595 " },
 596   { "decrypt", decrypt,
 597     "decrypt [-abqv] [-f FORMAT] [-o OUTPUT] [FILE]", "\
 598 Options:\n\
 599 \n\
 600 -a, --armour            Same as `-f pem'.\n\
 601 -b, --buffer            Buffer output until we're sure we have it all.\n\
 602 -f, --format=FORMAT     Decode as FORMAT.\n\
 603 -o, --output=FILE       Write output to FILE.\n\
 604 -q, --quiet             Produce fewer messages.\n\
 605 -v, --verbose           Produce more verbose messages.\n\
 606 " }, /* ' emacs is confused */
 607   { 0, 0, 0 }
 608 };
 609
 610 static int cmd_help(int argc, char **argv)
 611 {
 612   sc_help(cmdtab, stdout, argv + 1);
 613   return (0);
 614 }
 615
 616 void version(FILE *fp)
 617 {
 618   pquis(fp, "$, Catacomb version " VERSION "\n");
 619 }
 620
 621 static void usage(FILE *fp)
 622 {
 623   pquis(fp, "Usage: $ [-k KEYRING] COMMAND [ARGS]\n");
 624 }
 625
 626 void help_global(FILE *fp)
 627 {
 628   usage(fp);
 629   fputs("\n\
 630 Encrypt and decrypt files.\n\
 631 \n\
 632 Global command-line options:\n\
 633 \n\
 634 -h, --help [COMMAND...] Show this help message, or help for COMMANDs.\n\
 635 -v, --version           Show program version number.\n\
 636 -u, --usage             Show a terse usage message.\n\
 637 \n\
 638 -k, --keyring=FILE      Read keys from FILE.\n",
 639         fp);
 640 }
 641
 642 /* --- @main@ --- *
 643  *
 644  * Arguments:   @int argc@ = number of command line arguments
 645  *              @char *argv[]@ = vector of command line arguments
 646  *
 647  * Returns:     Zero if successful, nonzero otherwise.
 648  *
 649  * Use:         Encrypts or decrypts files.
 650  */
 651
 652 int main(int argc, char *argv[])
 653 {
 654   unsigned f = 0;
 655
 656 #define f_bogus 1u
 657
 658   /* --- Initialize the library --- */
 659
 660   ego(argv[0]);
 661   sub_init();
 662   rand_noisesrc(RAND_GLOBAL, &noise_source);
 663   rand_seed(RAND_GLOBAL, 160);
 664
 665   /* --- Parse options --- */
 666
 667   for (;;) {
 668     static struct option opts[] = {
 669       { "help",         0,              0,      'h' },
 670       { "version",      0,              0,      'v' },
 671       { "usage",        0,              0,      'u' },
 672       { "keyring",      OPTF_ARGREQ,    0,      'k' },
 673       { 0,              0,              0,      0 }
 674     };
 675     int i = mdwopt(argc, argv, "+hvu k:", opts, 0, 0, 0);
 676     if (i < 0)
 677       break;
 678     switch (i) {
 679       case 'h':
 680         sc_help(cmdtab, stdout, argv + optind);
 681         exit(0);
 682         break;
 683       case 'v':
 684         version(stdout);
 685         exit(0);
 686         break;
 687       case 'u':
 688         usage(stdout);
 689         exit(0);
 690       case 'k':
 691         keyring = optarg;
 692         break;
 693       default:
 694         f |= f_bogus;
 695         break;
 696     }
 697   }
 698
 699   argc -= optind;
 700   argv += optind;
 701   optind = 0;
 702   if (f & f_bogus || argc < 1) {
 703     usage(stderr);
 704     exit(EXIT_FAILURE);
 705   }
 706
 707   /* --- Dispatch to the correct subcommand handler --- */
 708
 709   return (findcmd(cmdtab, argv[0])->cmd(argc, argv));
 710
 711 #undef f_bogus
 712 }
 713
 714 /*----- That's all, folks -------------------------------------------------*/