Add cyclic group abstraction, with test code. Separate off exponentation

[u/mdw/catacomb] / keyutil.c

/* -*-c-*-
 *
 * $Id: keyutil.c,v 1.18 2004/04/01 12:50:09 mdw Exp $
 *
 * Simple key manager program
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * Catacomb is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: keyutil.c,v $
 * Revision 1.18  2004/04/01 12:50:09  mdw
 * Add cyclic group abstraction, with test code.  Separate off exponentation
 * functions for better static linking.  Fix a buttload of bugs on the way.
 * Generally ensure that negative exponents do inversion correctly.  Add
 * table of standard prime-field subgroups.  (Binary field subgroups are
 * currently unimplemented but easy to add if anyone ever finds a good one.)
 *
 * Revision 1.17  2004/03/28 01:58:47  mdw
 * Generate, store and retreive elliptic curve keys.
 *
 * Revision 1.16  2003/10/15 09:31:45  mdw
 * Fix help message.
 *
 * Revision 1.15  2003/05/15 23:23:24  mdw
 * Fix behaviour with bogus trailing attributes.
 *
 * Revision 1.14  2001/02/23 09:03:27  mdw
 * Simplify usage message by removing nonexistant options.
 *
 * Revision 1.13  2001/02/21 20:04:27  mdw
 * Provide help on individual commands (some need it desparately).  Allow
 * atomic retagging of keys.
 *
 * Revision 1.12  2001/02/03 11:58:22  mdw
 * Store the correct seed information and count for DSA keys now that it's
 * available.
 *
 * Revision 1.11  2000/12/06 20:33:27  mdw
 * Make flags be macros rather than enumerations, to ensure that they're
 * unsigned.
 *
 * Revision 1.10  2000/10/08 12:02:21  mdw
 * Use @MP_EQ@ instead of @MP_CMP@.
 *
 * Revision 1.9  2000/08/15 21:40:49  mdw
 * Minor formatting change in listing attributes.
 *
 * Revision 1.8  2000/07/29 09:59:13  mdw
 * Support Lim-Lee primes in Diffie-Hellman parameter generation.
 *
 * Revision 1.7  2000/07/01 11:18:51  mdw
 * Use new interfaces for key manipulation.
 *
 * Revision 1.6  2000/06/17 11:28:22  mdw
 * Use secure memory interface from MP library.  `rand_getgood' is
 * deprecated.
 *
 * Revision 1.5  2000/02/12 18:21:03  mdw
 * Overhaul of key management (again).
 *
 * Revision 1.4  1999/12/22 15:48:10  mdw
 * Track new key-management changes.  Support new key generation
 * algorithms.
 *
 * Revision 1.3  1999/11/02 15:23:24  mdw
 * Fix newlines in keyring list.
 *
 * Revision 1.2  1999/10/15 21:05:28  mdw
 * In `key list', show timezone for local times, and support `-u' option
 * for UTC output.
 *
 * Revision 1.1  1999/09/03 08:41:12  mdw
 * Initial import.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include "config.h"

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include <mLib/base64.h>
#include <mLib/mdwopt.h>
#include <mLib/quis.h>
#include <mLib/report.h>
#include <mLib/sub.h>

#include <noise.h>
#include <rand.h>

#include "bbs.h"
#include "dh.h"
#include "dsa.h"
#include "dsarand.h"
#include "ec.h"
#include "ec-keys.h"
#include "ectab.h"
#include "fibrand.h"
#include "getdate.h"
#include "key.h"
#include "mp.h"
#include "mpmont.h"
#include "mprand.h"
#include "mptext.h"
#include "pgen.h"
#include "rsa.h"

#include "sha-mgf.h"
#include "sha256-mgf.h"
#include "sha224-mgf.h"
#include "sha384-mgf.h"
#include "sha512-mgf.h"
#include "tiger-mgf.h"
#include "rmd128-mgf.h"
#include "rmd160-mgf.h"
#include "rmd256-mgf.h"
#include "rmd320-mgf.h"
#include "md5-mgf.h"
#include "dsarand.h"

/*----- Handy global state ------------------------------------------------*/

static const char *keyfile = "keyring";

/*----- Useful shared functions -------------------------------------------*/

/* --- @doopen@ --- *
 *
 * Arguments:   @key_file *f@ = pointer to key file block
 *              @unsigned how@ = method to open file with
 *
 * Returns:     ---
 *
 * Use:         Opens a key file and handles errors by panicking
 *              appropriately.
 */

static void doopen(key_file *f, unsigned how)
{
  if (key_open(f, keyfile, how, key_moan, 0))
    die(1, "couldn't open keyring `%s': %s", keyfile, strerror(errno));
}

/* --- @doclose@ --- *
 *
 * Arguments:   @key_file *f@ = pointer to key file block
 *
 * Returns:     ---
 *
 * Use:         Closes a key file and handles errors by panicking
 *              appropriately.
 */

static void doclose(key_file *f)
{
  switch (key_close(f)) {
    case KWRITE_FAIL:
      die(EXIT_FAILURE, "couldn't write file `%s': %s",
          keyfile, strerror(errno));
    case KWRITE_BROKEN:
      die(EXIT_FAILURE, "keyring file `%s' broken: %s (repair manually)",
          keyfile, strerror(errno));
  }
}

/* --- @setattr@ --- *
 *
 * Arguments:   @key_file *f@ = pointer to key file block
 *              @key *k@ = pointer to key block
 *              @char *v[]@ = array of assignments (overwritten!)
 *
 * Returns:     ---
 *
 * Use:         Applies the attribute assignments to the key.
 */

static void setattr(key_file *f, key *k, char *v[])
{
  while (*v) {
    int err;
    char *p = *v;
    size_t eq = strcspn(p, "=");
    if (!p[eq]) {
      moan("invalid assignment: `%s' (ignored)", p);
      v++;
      continue;
    }
    p[eq] = 0;
    p += eq + 1;
    if ((err = key_putattr(f, k, *v, *p ? p : 0)) != 0)
      die(EXIT_FAILURE, "couldn't set attributes: %s", key_strerror(err));
    v++;
  }
}

/*----- Seeding -----------------------------------------------------------*/

const struct seedalg { const char *p; grand *(*gen)(const void *, size_t); }
seedtab[] = {
  { "dsarand",  dsarand_create },
  { "rmd128-mgf",  rmd128_mgfrand },
  { "rmd160-mgf",  rmd160_mgfrand },
  { "rmd256-mgf",  rmd256_mgfrand },
  { "rmd320-mgf",  rmd320_mgfrand },
  { "sha-mgf",  sha_mgfrand },
  { "sha224-mgf",  sha224_mgfrand },
  { "sha256-mgf",  sha256_mgfrand },
  { "sha384-mgf",  sha384_mgfrand },
  { "sha512-mgf",  sha512_mgfrand },
  { "tiger-mgf",  tiger_mgfrand },
  { 0, 0 }
};

#define SEEDALG_DEFAULT (seedtab + 2)

/*----- Key generation ----------------------------------------------------*/

/* --- Key generation parameters --- */

typedef struct keyopts {
  key_file *kf;                         /* Pointer to key file */
  key *k;                               /* Pointer to the actual key */
  dstr tag;                             /* Full tag name for the key */
  unsigned f;                           /* Flags for the new key */
  unsigned bits, qbits;                 /* Bit length for the new key */
  const char *curve;                    /* Elliptic curve name/info */
  grand *r;                             /* Random number source */
  key *p;                               /* Parameters key-data */
} keyopts;

#define f_bogus 1u                      /* Error in parsing */
#define f_lock 2u                       /* Passphrase-lock private key */
#define f_quiet 4u                      /* Don't show a progress indicator */
#define f_limlee 8u                     /* Generate Lim-Lee primes */
#define f_subgroup 16u                  /* Generate a subgroup */
#define f_retag 32u                     /* Remove any existing tag */

/* --- @dolock@ --- *
 *
 * Arguments:   @keyopts *k@ = key generation options
 *              @key_data *kd@ = pointer to key data to lock
 *              @const char *t@ = tag suffix or null
 *
 * Returns:     ---
 *
 * Use:         Does passphrase locking on new keys.
 */

static void dolock(keyopts *k, key_data *kd, const char *t)
{
  if (!(k->f & f_lock))
    return;
  if (t)
    dstr_putf(&k->tag, ".%s", t);
  if (key_plock(k->tag.buf, kd, kd))
    die(EXIT_FAILURE, "couldn't lock key");
}

/* --- @mpkey@ --- *
 *
 * Arguments:   @key_data *kd@ = pointer to parent key block
 *              @const char *tag@ = pointer to tag string
 *              @mp *m@ = integer to store
 *              @unsigned f@ = flags to set
 *
 * Returns:     ---
 *
 * Use:         Sets a multiprecision integer subkey.
 */

static void mpkey(key_data *kd, const char *tag, mp *m, unsigned f)
{
  key_data *kkd = key_structcreate(kd, tag);
  key_mp(kkd, m);
  kkd->e |= f;
}

/* --- @copyparam@ --- *
 *
 * Arguments:   @keyopts *k@ = pointer to key options
 *              @const char **pp@ = checklist of parameters
 *
 * Returns:     Nonzero if parameters copied; zero if you have to generate
 *              them.
 *
 * Use:         Copies parameters from a source key to the current one.
 */

static int copyparam(keyopts *k, const char **pp)
{
  key_filter kf;

  /* --- Quick check if no parameters supplied --- */

  if (!k->p)
    return (0);

  /* --- Run through the checklist --- */

  while (*pp) {
    key_data *kd = key_structfind(&k->p->k, *pp);
    if (!kd)
      die(EXIT_FAILURE, "bad parameter key: parameter `%s' not found", *pp);
    if ((kd->e & KF_CATMASK) != KCAT_SHARE)
      die(EXIT_FAILURE, "bad parameter key: subkey `%s' is not shared", *pp);
    pp++;
  }

  /* --- Copy over the parameters --- */

  kf.f = KCAT_SHARE;
  kf.m = KF_CATMASK;
  if (!key_copy(&k->k->k, &k->p->k, &kf))
    die(EXIT_FAILURE, "unexpected failure while copying parameters");
  return (1);
}

/* --- @getmp@ --- *
 *
 * Arguments:   @key_data *k@ = pointer to key data block
 *              @const char *tag@ = tag string to use
 *
 * Returns:     Pointer to multiprecision integer key item.
 *
 * Use:         Fetches an MP key component.
 */

static mp *getmp(key_data *k, const char *tag)
{
  k = key_structfind(k, tag);
  if (!k)
    die(EXIT_FAILURE, "unexpected failure looking up subkey `%s'", tag);
  if ((k->e & KF_ENCMASK) != KENC_MP)
    die(EXIT_FAILURE, "subkey `%s' has an incompatible type");
  return (k->u.m);
}

/* --- @keyrand@ --- *
 *
 * Arguments:   @key_file *kf@ = pointer to key file
 *              @const char *id@ = pointer to key id (or null)
 *
 * Returns:     ---
 *
 * Use:         Keys the random number generator.
 */

static void keyrand(key_file *kf, const char *id)
{
  key *k;

  /* --- Find the key --- */

  if (id) {
    if ((k = key_bytag(kf, id)) == 0)
      die(EXIT_FAILURE, "key `%s' not found", id);
  } else
    k = key_bytype(kf, "catacomb-rand");

  if (k) {
    key_data *kd = &k->k, kkd;

  again:
    switch (kd->e & KF_ENCMASK) {
      case KENC_BINARY:
        break;
      case KENC_ENCRYPT: {
        dstr d = DSTR_INIT;
        key_fulltag(k, &d);
        if (key_punlock(d.buf, kd, &kkd))
          die(EXIT_FAILURE, "error unlocking key `%s'", d.buf);
        dstr_destroy(&d);
        kd = &kkd;
      } goto again;
      default: {
        dstr d = DSTR_INIT;
        key_fulltag(k, &d);
        die(EXIT_FAILURE, "bad encoding type for key `%s'", d.buf);
      } break;
    }

    /* --- Key the generator --- */

    rand_key(RAND_GLOBAL, kd->u.k.k, kd->u.k.sz);
    if (kd == &kkd)
      key_destroy(&kkd);
  }
}

/* --- Key generation algorithms --- */

static void alg_binary(keyopts *k)
{
  unsigned sz;
  unsigned m;
  octet *p;

  if (!k->bits)
    k->bits = 128;
  if (k->p)
    die(EXIT_FAILURE, "no shared parameters for binary keys");

  sz = (k->bits + 7) >> 3;
  p = sub_alloc(sz);
  m = (1 << (((k->bits - 1) & 7) + 1)) - 1;
  k->r->ops->fill(k->r, p, sz);
  *p &= m;
  key_binary(&k->k->k, p, sz);
  k->k->k.e |= KCAT_SYMM | KF_BURN;
  memset(p, 0, sz);
  sub_free(p, sz);
  dolock(k, &k->k->k, 0);
}

static void alg_des(keyopts *k)
{
  unsigned sz;
  octet *p;
  int i;

  if (!k->bits)
    k->bits = 168;
  if (k->p)
    die(EXIT_FAILURE, "no shared parameters for DES keys");
  if (k->bits % 56 || k->bits > 168)
    die(EXIT_FAILURE, "DES keys must be 56, 112 or 168 bits long");

  sz = k->bits / 7;
  p = sub_alloc(sz);
  k->r->ops->fill(k->r, p, sz);
  for (i = 0; i < sz; i++) {
    octet x = p[i] | 0x01;
    x = x ^ (x >> 4);
    x = x ^ (x >> 2);
    x = x ^ (x >> 1);
    p[i] = (p[i] & 0xfe) | (x & 0x01);
  }
  key_binary(&k->k->k, p, sz);
  k->k->k.e |= KCAT_SYMM | KF_BURN;
  memset(p, 0, sz);
  sub_free(p, sz);
  dolock(k, &k->k->k, 0);
}

static void alg_rsa(keyopts *k)
{
  rsa_priv rp;
  key_data *kd;

  /* --- Sanity checking --- */

  if (k->p)
    die(EXIT_FAILURE, "no shared parameters for RSA keys");
  if (!k->bits)
    k->bits = 1024;

  /* --- Generate the RSA parameters --- */

  if (rsa_gen(&rp, k->bits, k->r, 0,
              (k->f & f_quiet) ? 0 : pgen_ev, 0))
    die(EXIT_FAILURE, "RSA key generation failed");

  /* --- Run a test encryption --- */

  {
    grand *g = fibrand_create(k->r->ops->word(k->r));
    rsa_pub rpp;
    mp *m = mprand_range(MP_NEW, rp.n, g, 0);
    mp *c;

    rpp.n = rp.n;
    rpp.e = rp.e;
    c = rsa_qpubop(&rpp, MP_NEW, m);
    c = rsa_qprivop(&rp, c, c, g);

    if (!MP_EQ(c, m))
      die(EXIT_FAILURE, "test encryption failed");
    mp_drop(c);
    mp_drop(m);
    g->ops->destroy(g);
  }

  /* --- Allrighty then --- */

  kd = &k->k->k;
  key_structure(kd);
  mpkey(kd, "n", rp.n, KCAT_PUB);
  mpkey(kd, "e", rp.e, KCAT_PUB);

  kd = key_structcreate(kd, "private");
  key_structure(kd);
  mpkey(kd, "d", rp.d, KCAT_PRIV | KF_BURN);
  mpkey(kd, "p", rp.p, KCAT_PRIV | KF_BURN);
  mpkey(kd, "q", rp.q, KCAT_PRIV | KF_BURN);
  mpkey(kd, "q-inv", rp.q_inv, KCAT_PRIV | KF_BURN);
  mpkey(kd, "d-mod-p", rp.dp, KCAT_PRIV | KF_BURN);
  mpkey(kd, "d-mod-q", rp.dq, KCAT_PRIV | KF_BURN);
  dolock(k, kd, "private");

  rsa_privfree(&rp);
}

static void alg_dsaparam(keyopts *k)
{
  static const char *pl[] = { "q", "p", "g", 0 };
  if (!copyparam(k, pl)) {
    dsa_param dp;
    octet *p;
    size_t sz;
    dstr d = DSTR_INIT;
    base64_ctx c;
    key_data *kd = &k->k->k;
    dsa_seed ds;

    /* --- Choose appropriate bit lengths if necessary --- */

    if (!k->qbits)
      k->qbits = 160;
    if (!k->bits)
      k->bits = 768;

    /* --- Allocate a seed block --- */

    sz = (k->qbits + 7) >> 3;
    p = sub_alloc(sz);
    k->r->ops->fill(k->r, p, sz);

    /* --- Allocate the parameters --- */

    if (dsa_gen(&dp, k->qbits, k->bits, 0, p, sz, &ds,
                (k->f & f_quiet) ? 0 : pgen_ev, 0))
      die(EXIT_FAILURE, "DSA parameter generation failed");

    /* --- Store the parameters --- */

    key_structure(kd);
    mpkey(kd, "q", dp.q, KCAT_SHARE);
    mpkey(kd, "p", dp.p, KCAT_SHARE);
    mpkey(kd, "g", dp.g, KCAT_SHARE);
    mp_drop(dp.q);
    mp_drop(dp.p);
    mp_drop(dp.g);

    /* --- Store the seed for future verification --- */

    base64_init(&c);
    c.maxline = 0;
    c.indent = "";
    base64_encode(&c, ds.p, ds.sz, &d);
    base64_encode(&c, 0, 0, &d);
    key_putattr(k->kf, k->k, "seed", d.buf);
    DRESET(&d);
    dstr_putf(&d, "%u", ds.count);
    key_putattr(k->kf, k->k, "count", d.buf);
    xfree(ds.p);
    sub_free(p, sz);
    dstr_destroy(&d);
  }
}

static void alg_dsa(keyopts *k)
{
  mp *q, *p, *g;
  mp *x, *y;
  mpmont mm;
  key_data *kd = &k->k->k;

  /* --- Get the shared parameters --- */

  alg_dsaparam(k);
  q = getmp(kd, "q");
  p = getmp(kd, "p");
  g = getmp(kd, "g");

  /* --- Choose a private key --- */

  x = mprand_range(MP_NEWSEC, q, k->r, 0);
  mpmont_create(&mm, p);
  y = mpmont_exp(&mm, MP_NEW, g, x);

  /* --- Store everything away --- */

  mpkey(kd, "y", y, KCAT_PUB);

  kd = key_structcreate(kd, "private");
  key_structure(kd);
  mpkey(kd, "x", x, KCAT_PRIV | KF_BURN);
  dolock(k, kd, "private");

  mp_drop(x); mp_drop(y);
}

static void alg_dhparam(keyopts *k)
{
  static const char *pl[] = { "p", "q", "g", 0 };
  key_data *kd = &k->k->k;
  if (!copyparam(k, pl)) {
    dh_param dp;
    int rc;

    if (!k->bits)
      k->bits = 1024;

    /* --- Choose a large safe prime number --- */

    if (k->f & f_limlee) {
      mp **f;
      size_t nf;
      if (!k->qbits)
        k->qbits = 256;
      rc = dh_limlee(&dp, k->qbits, k->bits,
                     (k->f & f_subgroup) ? DH_SUBGROUP : 0,
                     0, k->r, (k->f & f_quiet) ? 0 : pgen_ev, 0,
                     (k->f & f_quiet) ? 0 : pgen_evspin, 0, &nf, &f);
      if (!rc) {
        dstr d = DSTR_INIT;
        size_t i;
        for (i = 0; i < nf; i++) {
          if (i)
            dstr_puts(&d, ", ");
          mp_writedstr(f[i], &d, 10);
          mp_drop(f[i]);
        }
        key_putattr(k->kf, k->k, "factors", d.buf);
        dstr_destroy(&d);
      }
    } else
      rc = dh_gen(&dp, k->qbits, k->bits, 0, k->r,
                  (k->f & f_quiet) ? 0 : pgen_ev, 0);

    if (rc)
      die(EXIT_FAILURE, "Diffie-Hellman parameter generation failed");

    key_structure(kd);
    mpkey(kd, "p", dp.p, KCAT_SHARE);
    mpkey(kd, "q", dp.q, KCAT_SHARE);
    mpkey(kd, "g", dp.g, KCAT_SHARE);
    mp_drop(dp.q);
    mp_drop(dp.p);
    mp_drop(dp.g);
  }
}

static void alg_dh(keyopts *k)
{
  mp *x, *y;
  mp *p, *q, *g;
  mpmont mm;
  key_data *kd = &k->k->k;

  /* --- Get the shared parameters --- */

  alg_dhparam(k);
  p = getmp(kd, "p");
  q = getmp(kd, "q");
  g = getmp(kd, "g");

  /* --- Choose a suitable private key --- *
   *
   * Since %$g$% has order %$q$%, choose %$x < q$%.
   */

  x = mprand_range(MP_NEWSEC, q, k->r, 0);

  /* --- Compute the public key %$y = g^x \bmod p$% --- */

  mpmont_create(&mm, p);
  y = mpmont_exp(&mm, MP_NEW, g, x);
  mpmont_destroy(&mm);

  /* --- Store everything away --- */

  mpkey(kd, "y", y, KCAT_PUB);

  kd = key_structcreate(kd, "private");
  key_structure(kd);
  mpkey(kd, "x", x, KCAT_PRIV | KF_BURN);
  dolock(k, kd, "private");

  mp_drop(x); mp_drop(y);
}

static void alg_bbs(keyopts *k)
{
  bbs_priv bp;
  key_data *kd;

  /* --- Sanity checking --- */

  if (k->p)
    die(EXIT_FAILURE, "no shared parameters for Blum-Blum-Shub keys");
  if (!k->bits)
    k->bits = 1024;

  /* --- Generate the BBS parameters --- */

  if (bbs_gen(&bp, k->bits, k->r, 0,
              (k->f & f_quiet) ? 0 : pgen_ev, 0))
    die(EXIT_FAILURE, "Blum-Blum-Shub key generation failed");

  /* --- Allrighty then --- */

  kd = &k->k->k;
  key_structure(kd);
  mpkey(kd, "n", bp.n, KCAT_PUB);

  kd = key_structcreate(kd, "private");
  key_structure(kd);
  mpkey(kd, "p", bp.p, KCAT_PRIV | KF_BURN);
  mpkey(kd, "q", bp.q, KCAT_PRIV | KF_BURN);
  dolock(k, kd, "private");

  bbs_privfree(&bp);
}

static void alg_ecparam(keyopts *k)
{
  static const char *pl[] = { "curve", 0 };
  if (!copyparam(k, pl)) {
    ec_info ei;
    const char *e;
    key_data *kd = &k->k->k;

    /* --- Decide on a curve --- */

    if (!k->bits) k->bits = 256;
    if (!k->curve) {
      if (k->bits <= 56) k->curve = "secp112r1";
      else if (k->bits <= 64) k->curve = "secp128r1";
      else if (k->bits <= 80) k->curve = "secp160r1";
      else if (k->bits <= 96) k->curve = "secp192r1";
      else if (k->bits <= 112) k->curve = "secp224r1";
      else if (k->bits <= 128) k->curve = "secp256r1";
      else if (k->bits <= 192) k->curve = "secp384r1";
      else if (k->bits <= 256) k->curve = "secp521r1";
      else
        die(EXIT_FAILURE, "no built-in curves provide %u-bit security",
            k->bits);
    }

    /* --- Check it --- */

    if ((e = ec_getinfo(&ei, k->curve)) != 0)
      die(EXIT_FAILURE, "error in curve spec: %s", e);
    if (!(k->f & f_quiet) && (e = ec_checkinfo(&ei, k->r)) != 0)
      moan("WARNING!  curve check failed: %s", e);
    ec_freeinfo(&ei);

    /* --- Write out the answer --- */

    key_structure(kd);
    kd = key_structcreate(kd, "curve");
    key_string(kd, k->curve);
    kd->e |= KCAT_SHARE;
  }
}

static void alg_ec(keyopts *k)
{
  key_data *kd = &k->k->k;
  key_data *kkd;
  mp *x = MP_NEW;
  ec p = EC_INIT;
  const char *e;
  ec_info ei;

  /* --- Get the curve --- */

  alg_ecparam(k);
  if ((kkd = key_structfind(kd, "curve")) == 0)
    die(EXIT_FAILURE, "unexpected failure looking up subkey `curve')");
  if ((kkd->e & KF_ENCMASK) != KENC_STRING)
    die(EXIT_FAILURE, "subkey `curve' is not a string");
  if ((e = ec_getinfo(&ei, kkd->u.p)) != 0)
    die(EXIT_FAILURE, "error in curve spec: %s", e);

  /* --- Invent a private exponent and compute the public key --- */

  x = mprand_range(MP_NEWSEC, ei.r, k->r, 0);
  ec_mul(ei.c, &p, &ei.g, x);

  /* --- Store everything away --- */

  kkd = key_structcreate(kd, "p");
  key_ec(kkd, &p);
  kkd->e |= KCAT_PUB;
  kkd = key_structcreate(kd, "private");
  key_structure(kkd);
  mpkey(kkd, "x", x, KCAT_PRIV | KF_BURN);

  /* --- Done --- */

  ec_freeinfo(&ei);
  mp_drop(x);
}

/* --- The algorithm tables --- */

typedef struct keyalg {
  const char *name;
  void (*proc)(keyopts *o);
  const char *help;
} keyalg;

static keyalg algtab[] = {
  { "binary",           alg_binary,     "Plain binary data" },
  { "des",              alg_des,        "Binary with DES-style parity" },
  { "rsa",              alg_rsa,        "RSA public-key encryption" },
  { "dsa",              alg_dsa,        "DSA digital signatures" },
  { "dsa-param",        alg_dsaparam,   "DSA shared parameters" },
  { "dh",               alg_dh,         "Diffie-Hellman key exchange" },
  { "dh-param",         alg_dhparam,    "Diffie-Hellman parameters" },
  { "bbs",              alg_bbs,        "Blum-Blum-Shub generator" },
  { "ec-param",         alg_ecparam,    "Elliptic curve parameters" },
  { "ec",               alg_ec,         "Elliptic curve crypto" },
  { 0,                  0 }
};

/* --- @cmd_add@ --- */

static int cmd_add(int argc, char *argv[])
{
  key_file f;
  time_t exp = KEXP_EXPIRE;
  const char *tag = 0, *ptag = 0;
  const char *c = 0;
  keyalg *alg = algtab;
  const char *rtag = 0;
  const struct seedalg *sa = SEEDALG_DEFAULT;
  keyopts k = { 0, 0, DSTR_INIT, 0, 0, 0, 0, 0 };
  const char *seed = 0;
  k.r = &rand_global;

  /* --- Parse options for the subcommand --- */

  for (;;) {
    static struct option opt[] = {
      { "algorithm",    OPTF_ARGREQ,    0,      'a' },
      { "bits",         OPTF_ARGREQ,    0,      'b' },
      { "qbits",        OPTF_ARGREQ,    0,      'B' },
      { "parameters",   OPTF_ARGREQ,    0,      'p' },
      { "expire",       OPTF_ARGREQ,    0,      'e' },
      { "comment",      OPTF_ARGREQ,    0,      'c' },
      { "tag",          OPTF_ARGREQ,    0,      't' },
      { "rand-id",      OPTF_ARGREQ,    0,      'R' },
      { "curve",        OPTF_ARGREQ,    0,      'C' },
      { "seedalg",      OPTF_ARGREQ,    0,      'A' },
      { "seed",         OPTF_ARGREQ,    0,      's' },
      { "newseed",      OPTF_ARGREQ,    0,      'n' },
      { "lock",         0,              0,      'l' },
      { "quiet",        0,              0,      'q' },
      { "lim-lee",      0,              0,      'L' },
      { "subgroup",     0,              0,      'S' },
      { 0,              0,              0,      0 }
    };
    int i = mdwopt(argc, argv, "+a:b:B:p:e:c:t:R:C:A:s:n:lqrLS", opt, 0, 0, 0);
    if (i < 0)
      break;

    /* --- Handle the various options --- */

    switch (i) {

      /* --- Read an algorithm name --- */

      case 'a': {
        keyalg *a;
        size_t sz = strlen(optarg);

        if (strcmp(optarg, "list") == 0) {
          for (a = algtab; a->name; a++)
            printf("%-10s %s\n", a->name, a->help);
          return (0);
        }

        alg = 0;
        for (a = algtab; a->name; a++) {
          if (strncmp(optarg, a->name, sz) == 0) {
            if (a->name[sz] == 0) {
              alg = a;
              break;
            } else if (alg)
              die(EXIT_FAILURE, "ambiguous algorithm name `%s'", optarg);
            else
              alg = a;
          }
        }
        if (!alg)
          die(EXIT_FAILURE, "unknown algorithm name `%s'", optarg);
      } break;

      /* --- Bits must be nonzero and a multiple of 8 --- */

      case 'b': {
        char *p;
        k.bits = strtoul(optarg, &p, 0);
        if (k.bits == 0 || *p != 0)
          die(EXIT_FAILURE, "bad bitlength `%s'", optarg);
      } break;

      case 'B': {
        char *p;
        k.qbits = strtoul(optarg, &p, 0);
        if (k.qbits == 0 || *p != 0)
          die(EXIT_FAILURE, "bad bitlength `%s'", optarg);
      } break;

      /* --- Parameter selection --- */

      case 'p':
        ptag = optarg;
        break;

      /* --- Expiry dates get passed to @get_date@ for parsing --- */

      case 'e':
        if (strncmp(optarg, "forever", strlen(optarg)) == 0)
          exp = KEXP_FOREVER;
        else {
          exp = get_date(optarg, 0);
          if (exp == -1)
            die(EXIT_FAILURE, "bad expiry date `%s'", optarg);
        }
        break;

      /* --- Store comments without interpretation --- */

      case 'c':
        if (key_chkcomment(optarg))
          die(EXIT_FAILURE, "bad comment string `%s'", optarg);
        c = optarg;
        break;

      /* --- Elliptic curve parameters --- */

      case 'C':
        if (strcmp(optarg, "list") == 0) {
          const ecentry *ee;
          printf("Built-in elliptic curves:\n");
          for (ee = ectab; ee->name; ee++)
            printf("  %s\n", ee->name);
          exit(0);
        }
        k.curve = optarg;
        break;

      /* --- Store tags --- */

      case 't':
        if (key_chkident(optarg))
          die(EXIT_FAILURE, "bad tag string `%s'", optarg);
        tag = optarg;
        break;
      case 'r':
        k.f |= f_retag;
        break;

      /* --- Seeding --- */

      case 'A': {
        const struct seedalg *ss;
        if (strcmp(optarg, "list") == 0) {
          printf("Seed algorithms:\n");
          for (ss = seedtab; ss->p; ss++)
            printf("  %s\n", ss->p);
          exit(0);
        }
        if (seed) die(EXIT_FAILURE, "seed already set -- put -A first");
        sa = 0;
        for (ss = seedtab; ss->p; ss++) {
          if (strcmp(optarg, ss->p) == 0)
            sa = ss;
        }
        if (!sa)
          die(EXIT_FAILURE, "seed algorithm `%s' not known", optarg);
      } break;

      case 's': {
        base64_ctx b;
        dstr d = DSTR_INIT;
        if (seed) die(EXIT_FAILURE, "seed already set"); 
        base64_init(&b);
        base64_decode(&b, optarg, strlen(optarg), &d);
        base64_decode(&b, 0, 0, &d);
        k.r = sa->gen(d.buf, d.len);
        seed = optarg;
        dstr_destroy(&d);
      } break;
        
      case 'n': {
        base64_ctx b;
        dstr d = DSTR_INIT;
        char *p;
        unsigned n = strtoul(optarg, &p, 0);
        if (n == 0 || *p != 0 || n % 8 != 0)
          die(EXIT_FAILURE, "bad seed length `%s'", optarg);
        if (seed) die(EXIT_FAILURE, "seed already set"); 
        n /= 8;
        p = xmalloc(n);
        rand_get(RAND_GLOBAL, p, n);
        base64_init(&b);
        base64_encode(&b, p, n, &d);
        base64_encode(&b, 0, 0, &d);
        seed = d.buf;
        k.r = sa->gen(p, n);
      } break;
        
      /* --- Other flags --- */

      case 'R':
        rtag = optarg;
        break;
      case 'l':
        k.f |= f_lock;
        break;
      case 'q':
        k.f |= f_quiet;
        break;
      case 'L':
        k.f |= f_limlee;
        break;
      case 'S':
        k.f |= f_subgroup;
        break;

      /* --- Other things are bogus --- */

      default:
        k.f |= f_bogus;
        break;
    }
  }

  /* --- Various sorts of bogosity --- */

  if ((k.f & f_bogus) || optind + 1 > argc) {
    die(EXIT_FAILURE,
        "Usage: add [options] type [attr...]");
  }
  if (key_chkident(argv[optind]))
    die(EXIT_FAILURE, "bad key type `%s'", argv[optind]);

  /* --- Set up various bits of the state --- */

  if (exp == KEXP_EXPIRE)
    exp = time(0) + 14 * 24 * 60 * 60;

  /* --- Open the file and create the basic key block --- *
   *
   * Keep on generating keyids until one of them doesn't collide.
   */

  doopen(&f, KOPEN_WRITE);
  k.kf = &f;

  /* --- Key the generator --- */

  keyrand(&f, rtag);

  for (;;) {
    uint32 id = rand_global.ops->word(&rand_global);
    int err;
    k.k = key_new(&f, id, argv[optind], exp, &err);
    if (k.k)
      break;
    if (err != KERR_DUPID)
      die(EXIT_FAILURE, "error adding new key: %s", key_strerror(err));
  }

  /* --- Set various simple attributes --- */

  if (tag) {
    int err;
    key *kk;
    if (k.f & f_retag) {
      if ((kk = key_bytag(&f, tag)) != 0 && strcmp(kk->tag, tag) == 0)
        key_settag(&f, kk, 0);
    }
    if ((err = key_settag(&f, k.k, tag)) != 0)
      die(EXIT_FAILURE, "error setting key tag: %s", key_strerror(err));
  }

  if (c) {
    int err = key_setcomment(&f, k.k, c);
    if (err)
      die(EXIT_FAILURE, "error setting key comment: %s", key_strerror(err));
  }

  setattr(&f, k.k, argv + optind + 1);
  if (seed) {
    key_putattr(&f, k.k, "genseed", seed);
    key_putattr(&f, k.k, "seedalg", sa->p);
  }

  key_fulltag(k.k, &k.tag);

  /* --- Find the parameter key --- */

  if (ptag) {
    if ((k.p = key_bytag(&f, ptag)) == 0)
      die(EXIT_FAILURE, "parameter key `%s' not found", ptag);
    if ((k.p->k.e & KF_ENCMASK) != KENC_STRUCT)
      die(EXIT_FAILURE, "parameter key `%s' is not structured", ptag);
  }

  /* --- Now generate the actual key data --- */

  alg->proc(&k);

  /* --- Done --- */

  doclose(&f);
  return (0);
}

/*----- Key listing -------------------------------------------------------*/

/* --- Listing options --- */

typedef struct listopts {
  const char *tfmt;                     /* Date format (@strftime@-style) */
  int v;                                /* Verbosity level */
  unsigned f;                           /* Various flags */
  time_t t;                             /* Time now (for key expiry) */
  key_filter kf;                        /* Filter for matching keys */
} listopts;

/* --- Listing flags --- */

#define f_newline 2u                    /* Write newline before next entry */
#define f_attr 4u                       /* Written at least one attribute */
#define f_utc 8u                        /* Emit UTC time, not local time */

/* --- @showkeydata@ --- *
 *
 * Arguments:   @key_data *k@ = pointer to key to write
 *              @int ind@ = indentation level
 *              @listopts *o@ = listing options
 *              @dstr *d@ = tag string for this subkey
 *
 * Returns:     ---
 *
 * Use:         Emits a piece of key data in a human-readable format.
 */

static void showkeydata(key_data *k, int ind, listopts *o, dstr *d)
{
#define INDENT(i) do {                                                  \
  int _i;                                                               \
  for (_i = 0; _i < (i); _i++) {                                        \
    putchar(' ');                                                       \
  }                                                                     \
} while (0)

  switch (k->e & KF_ENCMASK) {

    /* --- Binary key data --- *
     *
     * Emit as a simple hex dump.
     */

    case KENC_BINARY: {
      const octet *p = k->u.k.k;
      const octet *l = p + k->u.k.sz;
      size_t sz = 0;

      fputs(" {", stdout);
      while (p < l) {
        if (sz % 16 == 0) {
          putchar('\n');
          INDENT(ind + 2);
        } else if (sz % 8 == 0)
          fputs("  ", stdout);
        else
          putc(' ', stdout);
        printf("%02x", *p++);
        sz++;
      }
      putchar('\n');
      INDENT(ind);
      fputs("}\n", stdout);
    } break;

    /* --- Encrypted data --- *
     *
     * If the user is sufficiently keen, ask for a passphrase and decrypt the
     * key.  Otherwise just say that it's encrypted and move on.
     */

    case KENC_ENCRYPT:
      if (o->v <= 3)
        fputs(" encrypted\n", stdout);
      else {
        key_data kd;
        if (key_punlock(d->buf, k, &kd))
          printf(" <failed to unlock %s>\n", d->buf);
        else {
          fputs(" encrypted", stdout);
          showkeydata(&kd, ind, o, d);
          key_destroy(&kd);
        }
      }
      break;

    /* --- Integer keys --- *
     *
     * Emit as a large integer in decimal.  This makes using the key in
     * `calc' or whatever easier.
     */

    case KENC_MP:
      putchar(' ');
      mp_writefile(k->u.m, stdout, 10);
      putchar('\n');
      break;

    /* --- Strings --- */

    case KENC_STRING:
      printf(" `%s'\n", k->u.p);
      break;

    /* --- Elliptic curve points --- */

    case KENC_EC:
      fputs(" 0x", stdout); mp_writefile(k->u.e.x, stdout, 16);
      fputs(", 0x", stdout); mp_writefile(k->u.e.y, stdout, 16);
      putchar('\n');
      break;      

    /* --- Structured keys --- *
     *
     * Just iterate over the subkeys.
     */

    case KENC_STRUCT: {
      sym_iter i;
      key_struct *ks;
      size_t n = d->len;

      fputs(" {\n", stdout);
      for (sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; ) {
        if (!key_match(&ks->k, &o->kf))
          continue;
        INDENT(ind + 2);
        printf("%s =", SYM_NAME(ks));
        d->len = n;
        dstr_putf(d, ".%s", SYM_NAME(ks));
        showkeydata(&ks->k, ind + 2, o, d);
      }
      INDENT(ind);
      fputs("}\n", stdout);
    } break;      
  }

#undef INDENT
}

/* --- @showkey@ --- *
 *
 * Arguments:   @key *k@ = pointer to key to show
 *              @listopts *o@ = pointer to listing options
 *
 * Returns:     ---
 *
 * Use:         Emits a listing of a particular key.
 */

static void showkey(key *k, listopts *o)
{
  char ebuf[24], dbuf[24];
  struct tm *tm;

  /* --- Skip the key if the filter doesn't match --- */

  if (!key_match(&k->k, &o->kf))
    return;

  /* --- Sort out the expiry and deletion times --- */

  if (KEY_EXPIRED(o->t, k->exp))
    strcpy(ebuf, "expired");
  else if (k->exp == KEXP_FOREVER)
    strcpy(ebuf, "forever");
  else {
    tm = (o->f & f_utc) ? gmtime(&k->exp) : localtime(&k->exp);
    strftime(ebuf, sizeof(ebuf), o->tfmt, tm);
  }

  if (KEY_EXPIRED(o->t, k->del))
    strcpy(dbuf, "deleted");
  else if (k->del == KEXP_FOREVER)
    strcpy(dbuf, "forever");
  else {
    tm = (o->f & f_utc) ? gmtime(&k->del) : localtime(&k->del);
    strftime(dbuf, sizeof(dbuf), o->tfmt, tm);
  }

  /* --- If in compact format, just display and quit --- */

  if (!o->v) {
    if (!(o->f & f_newline)) {
      printf("%8s  %-20s  %-20s  %-10s  %-10s\n",
             "Id", "Tag", "Type", "Expire", "Delete");
    }
    printf("%08lx  %-20s  %-20s  %-10s  %-10s\n",
           (unsigned long)k->id, k->tag ? k->tag : "<none>",
           k->type, ebuf, dbuf);
    o->f |= f_newline;
    return;
  }

  /* --- Display the standard header --- */

  if (o->f & f_newline)
    fputc('\n', stdout);
  printf("keyid: %08lx\n", (unsigned long)k->id);
  printf("tag: %s\n", k->tag ? k->tag : "<none>");
  printf("type: %s\n", k->type);
  printf("expiry: %s\n", ebuf);
  printf("delete: %s\n", dbuf);
  printf("comment: %s\n", k->c ? k->c : "<none>");

  /* --- Display the attributes --- */

  if (o->v > 1) {
    key_attriter i;
    const char *av, *an;

    o->f &= ~f_attr;
    printf("attributes:");
    for (key_mkattriter(&i, k); key_nextattr(&i, &an, &av); ) {
      printf("\n  %s = %s", an, av);
      o->f |= f_attr;
    }
    if (o->f & f_attr)
      fputc('\n', stdout);
    else
      puts(" <none>");
  }

  /* --- If dumping requested, dump the raw key data --- */

  if (o->v > 2) {
    dstr d = DSTR_INIT;
    fputs("key:", stdout);
    key_fulltag(k, &d);
    showkeydata(&k->k, 0, o, &d);
    dstr_destroy(&d);
  }
    
  o->f |= f_newline;
}

/* --- @cmd_list@ --- */

static int cmd_list(int argc, char *argv[])
{
  key_file f;
  key *k;
  listopts o = { 0, 0, 0, 0, { 0, 0 } };

  /* --- Parse subcommand options --- */

  for (;;) {
    static struct option opt[] = {
      { "quiet",        0,              0,      'q' },
      { "verbose",      0,              0,      'v' },
      { "utc",          0,              0,      'u' },
      { "filter",       OPTF_ARGREQ,    0,      'f' },
      { 0,              0,              0,      0 }
    };
    int i = mdwopt(argc, argv, "+uqvf:", opt, 0, 0, 0);
    if (i < 0)
      break;

    switch (i) {
      case 'u':
        o.f |= f_utc;
        break;
      case 'q':
        if (o.v)
          o.v--;
        break;
      case 'v':
        o.v++;
        break;
      case 'f': {
        char *p;
        int e = key_readflags(optarg, &p, &o.kf.f, &o.kf.m);
        if (e || *p)
          die(EXIT_FAILURE, "bad filter string `%s'", optarg);
      } break;  
      default:
        o.f |= f_bogus;
        break;
    }
  }

  if (o.f & f_bogus)
    die(EXIT_FAILURE, "Usage: list [-uqv] [-f filter] [tag...]");

  /* --- Open the key file --- */

  doopen(&f, KOPEN_READ);
  o.t = time(0);

  /* --- Set up the time format --- */

  if (!o.v)
    o.tfmt = "%Y-%m-%d";
  else if (o.f & f_utc)
    o.tfmt = "%Y-%m-%d %H:%M:%S UTC";
  else
    o.tfmt = "%Y-%m-%d %H:%M:%S %Z";

  /* --- If specific keys were requested use them, otherwise do all --- *
   *
   * Some day, this might turn into a wildcard match.
   */

  if (optind < argc) {
    do {
      if ((k = key_bytag(&f, argv[optind])) != 0)
        showkey(k, &o);
      else {
        moan("key `%s' not found", argv[optind]);
        o.f |= f_bogus;
      }
      optind++;
    } while (optind < argc);
  } else {
    key_iter i;
    for (key_mkiter(&i, &f); (k = key_next(&i)) != 0; )
      showkey(k, &o);
  }

  /* --- Done --- */

  doclose(&f);
  if (o.f & f_bogus)
    return (EXIT_FAILURE);
  else
    return (0);
}

/*----- Command implementation --------------------------------------------*/

/* --- @cmd_expire@ --- */

static int cmd_expire(int argc, char *argv[])
{
  key_file f;
  key *k;
  int i;
  int rc = 0;

  if (argc < 2)
    die(EXIT_FAILURE, "Usage: expire tag...");
  doopen(&f, KOPEN_WRITE);
  for (i = 1; i < argc; i++) {
    if ((k = key_bytag(&f, argv[i])) != 0)
      key_expire(&f, k);
    else {
      moan("key `%s' not found", argv[i]);
      rc = 1;
    }
  }
  doclose(&f);
  return (rc);
}

/* --- @cmd_delete@ --- */

static int cmd_delete(int argc, char *argv[])
{
  key_file f;
  key *k;
  int i;
  int rc = 0;

  if (argc < 2)
    die(EXIT_FAILURE, "Usage: delete tag...");
  doopen(&f, KOPEN_WRITE);
  for (i = 1; i < argc; i++) {
    if ((k = key_bytag(&f, argv[i])) != 0)
      key_delete(&f, k);
    else {
      moan("key `%s' not found", argv[i]);
      rc = 1;
    }
  }
  doclose(&f);
  return (rc);
}

/* --- @cmd_setattr@ --- */

static int cmd_setattr(int argc, char *argv[])
{
  key_file f;
  key *k;

  if (argc < 3)
    die(EXIT_FAILURE, "Usage: setattr tag attr...");
  doopen(&f, KOPEN_WRITE);
  if ((k = key_bytag(&f, argv[1])) == 0)
    die(EXIT_FAILURE, "key `%s' not found", argv[1]);
  setattr(&f, k, argv + 2);
  doclose(&f);
  return (0);
}

/* --- @cmd_finger@ --- */

static void fingerprint(key *k, const key_filter *kf)
{
  rmd160_ctx r;
  octet hash[RMD160_HASHSZ];
  dstr d = DSTR_INIT;
  int i;

  if (!key_encode(&k->k, &d, kf))
    return;
  rmd160_init(&r);
  rmd160_hash(&r, d.buf, d.len);
  rmd160_done(&r, hash);

  DRESET(&d);
  key_fulltag(k, &d);
  for (i = 0; i < sizeof(hash); i++) {
    if (i && i % 4 == 0)
      putchar('-');
    printf("%02x", hash[i]);
  }
  printf(" %s\n", d.buf);
  dstr_destroy(&d);
}

static int cmd_finger(int argc, char *argv[])
{
  key_file f;
  int rc = 0;
  key_filter kf = { KF_NONSECRET, KF_NONSECRET };

  for (;;) {
    static struct option opt[] = {
      { "filter",       OPTF_ARGREQ,    0,      'f' },
      { 0,              0,              0,      0 }
    };
    int i = mdwopt(argc, argv, "+f:", opt, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'f': {
        char *p;
        int err = key_readflags(optarg, &p, &kf.f, &kf.m);
        if (err || *p)
          die(EXIT_FAILURE, "bad filter string `%s'", optarg);
      } break;
      default:
        rc = 1;
        break;
    }
  }

  argv += optind; argc -= optind;
  if (rc)
    die(EXIT_FAILURE, "Usage: fingerprint [-f filter] [tag...]");

  doopen(&f, KOPEN_READ);

  if (argc) {
    int i;
    for (i = 0; i < argc; i++) {
      key *k = key_bytag(&f, argv[i]);
      if (k)
        fingerprint(k, &kf);
      else {
        rc = 1;
        moan("key `%s' not found", argv[i]);
      }
    }
  } else {
    key_iter i;
    key *k;
    for (key_mkiter(&i, &f); (k = key_next(&i)) != 0; )
      fingerprint(k, &kf);
  }
  return (rc);
}

/* --- @cmd_comment@ --- */

static int cmd_comment(int argc, char *argv[])
{
  key_file f;
  key *k;
  int err;

  if (argc < 2 || argc > 3)
    die(EXIT_FAILURE, "Usage: comment tag [comment]");
  doopen(&f, KOPEN_WRITE);
  if ((k = key_bytag(&f, argv[1])) == 0)
    die(EXIT_FAILURE, "key `%s' not found", argv[1]);
  if ((err = key_setcomment(&f, k, argv[2])) != 0)
    die(EXIT_FAILURE, "bad comment `%s': %s", argv[2], key_strerror(err));
  doclose(&f);
  return (0);
}

/* --- @cmd_tag@ --- */

static int cmd_tag(int argc, char *argv[])
{
  key_file f;
  key *k;
  int err;
  unsigned flags = 0;
  int rc = 0;

  for (;;) {
    static struct option opt[] = {
      { "retag",        0,              0,      'r' },
      { 0,              0,              0,      0 }
    };
    int i = mdwopt(argc, argv, "+r", opt, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'r':
        flags |= f_retag;
        break;
      default:
        rc = 1;
        break;
    }
  }

  argv += optind; argc -= optind;
  if (argc < 1 || argc > 2 || rc)
    die(EXIT_FAILURE, "Usage: tag [-r] tag [new-tag]");
  doopen(&f, KOPEN_WRITE);
  if (flags & f_retag) {
    if ((k = key_bytag(&f, argv[1])) != 0 && strcmp(k->tag, argv[1]) == 0)
      key_settag(&f, k, 0);
  }
  if ((k = key_bytag(&f, argv[0])) == 0)
    die(EXIT_FAILURE, "key `%s' not found", argv[0]);
  if ((err = key_settag(&f, k, argv[1])) != 0)
    die(EXIT_FAILURE, "bad tag `%s': %s", argv[1], key_strerror(err));
  doclose(&f);
  return (0);
}

/* --- @cmd_lock@ --- */

static int cmd_lock(int argc, char *argv[])
{
  key_file f;
  key *k;
  key_data *kd;
  dstr d = DSTR_INIT;

  if (argc != 2)
    die(EXIT_FAILURE, "Usage: lock qtag");
  doopen(&f, KOPEN_WRITE);
  if (key_qtag(&f, argv[1], &d, &k, &kd))
    die(EXIT_FAILURE, "key `%s' not found", argv[1]);
  if (kd->e == KENC_ENCRYPT && key_punlock(d.buf, kd, kd))
    die(EXIT_FAILURE, "couldn't unlock key `%s'", d.buf);
  if (key_plock(d.buf, kd, kd))
    die(EXIT_FAILURE, "failed to lock key `%s'", d.buf);
  f.f |= KF_MODIFIED;
  doclose(&f);
  return (0);
}

/* --- @cmd_unlock@ --- */

static int cmd_unlock(int argc, char *argv[])
{
  key_file f;
  key *k;
  key_data *kd;
  dstr d = DSTR_INIT;

  if (argc != 2)
    die(EXIT_FAILURE, "Usage: unlock qtag");
  doopen(&f, KOPEN_WRITE);
  if (key_qtag(&f, argv[1], &d, &k, &kd))
    die(EXIT_FAILURE, "key `%s' not found", argv[1]);
  if (kd->e != KENC_ENCRYPT)
    die(EXIT_FAILURE, "key `%s' is not encrypted", d.buf);
  if (kd->e == KENC_ENCRYPT && key_punlock(d.buf, kd, kd))
    die(EXIT_FAILURE, "couldn't unlock key `%s'", d.buf);
  f.f |= KF_MODIFIED;
  doclose(&f);
  return (0);
}

/* --- @cmd_extract@ --- */

static int cmd_extract(int argc, char *argv[])
{
  key_file f;
  key *k;
  int i;
  int rc = 0;
  key_filter kf = { 0, 0 };
  FILE *fp;

  for (;;) {
    static struct option opt[] = {
      { "filter",       OPTF_ARGREQ,    0,      'f' },
      { 0,              0,              0,      0 }
    };
    int i = mdwopt(argc, argv, "f:", opt, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'f': {
        char *p;
        int err = key_readflags(optarg, &p, &kf.f, &kf.m);
        if (err || *p)
          die(EXIT_FAILURE, "bad filter string `%s'", optarg);
      } break;
      default:
        rc = 1;
        break;
    }
  }

  argv += optind; argc -= optind;
  if (rc || argc < 1)
    die(EXIT_FAILURE, "Usage: extract [-f filter] file [tag...]");
  if (strcmp(*argv, "-") == 0)
    fp = stdout;
  else if (!(fp = fopen(*argv, "w"))) {
    die(EXIT_FAILURE, "couldn't open `%s' for writing: %s",
        *argv, strerror(errno));
  }

  doopen(&f, KOPEN_READ);
  if (argc < 2) {
    key_iter i;
    key *k;
    for (key_mkiter(&i, &f); (k = key_next(&i)) != 0; )
      key_extract(&f, k, fp, &kf);
  } else {    
    for (i = 1; i < argc; i++) {
      if ((k = key_bytag(&f, argv[i])) != 0)
        key_extract(&f, k, fp, &kf);
      else {
        moan("key `%s' not found", argv[i]);
        rc = 1;
      }
    }
  }
  if (fclose(fp))
    die(EXIT_FAILURE, "error writing file: %s", strerror(errno));
  doclose(&f);
  return (rc);
}

/* --- @cmd_tidy@ --- */

static int cmd_tidy(int argc, char *argv[])
{
  key_file f;
  if (argc != 1)
    die(EXIT_FAILURE, "usage: tidy");
  doopen(&f, KOPEN_WRITE);
  f.f |= KF_MODIFIED; /* Nasty hack */
  doclose(&f);
  return (0);
}

/* --- @cmd_merge@ --- */

static int cmd_merge(int argc, char *argv[])
{
  key_file f;
  FILE *fp;

  if (argc != 2)
    die(EXIT_FAILURE, "Usage: merge file");
  if (strcmp(argv[1], "-") == 0)
    fp = stdin;
  else if (!(fp = fopen(argv[1], "r"))) {
    die(EXIT_FAILURE, "couldn't open `%s' for writing: %s",
        argv[1], strerror(errno));
  }

  doopen(&f, KOPEN_WRITE);
  key_merge(&f, argv[1], fp, key_moan, 0);
  doclose(&f);
  return (0);
}

/*----- Main command table ------------------------------------------------*/

static struct cmd {
  const char *name;
  int (*cmd)(int /*argc*/, char */*argv*/[]);
  const char *usage;
  const char *help;
} cmds[] = {
  { "add", cmd_add,
    "add [options] type [attr...]\n\
        Options: [-lqrLS] [-a alg] [-bB bits] [-p param] [-R tag]\n\
                 [-e expire] [-t tag] [-c comment]", "\
Options:\n\
\n\
-a, --algorithm=ALG     Generate keys suitable for ALG.\n\
-b, --bits=N            Generate an N-bit key.\n\
-B, --qbits=N           Use an N-bit subgroup or factors.\n\
-p, --parameters=TAG    Get group parameters from TAG.\n\
-C, --curve=CURVE       Use elliptic curve CURVE.\n\
-e, --expire=TIME       Make the key expire after TIME.\n\
-c, --comment=STRING    Attach the command STRING to the key.\n\
-t, --tag=TAG           Tag the key with the name TAG.\n\
-r, --retag             Untag any key currently with that tag.\n\
-R, --rand-id=TAG       Use key named TAG for the random number generator.\n\
-l, --lock              Lock the generated key with a passphrase.\n\
-q, --quiet             Don't give progress indicators while working.\n\
-L, --lim-lee           Generate Lim-Lee primes for Diffie-Hellman groups.\n\
-S, --subgroup          Use a prime-order subgroup for Diffie-Hellman.\n\
" },
  { "expire", cmd_expire, "expire tag..." },
  { "delete", cmd_delete, "delete tag..." },
  { "tag", cmd_tag, "tag [-r] tag [new-tag]", "\
Options:\n\
\n\
-r, --retag             Untag any key currently called new-tag.\n\
" },
  { "setattr", cmd_setattr, "setattr tag attr..." },
  { "comment", cmd_comment, "comment tag [comment]" },
  { "lock", cmd_lock, "lock qtag" },
  { "unlock", cmd_unlock, "unlock qtag" },
  { "list", cmd_list, "list [-uqv] [-f filter] [tag...]", "\
Options:\n\
\n\
-u, --utc               Display expiry times etc. in UTC, not local time.\n\
-q, --quiet             Show less information.\n\
-v, --verbose           Show more information.\n\
" },
  { "fingerprint", cmd_finger, "fingerprint [-f filter] [tag...]", "\
Options:\n\
\n\
-f, --filter=FILT       Only hash key components matching FILT.\n\
" },
  { "tidy", cmd_tidy, "tidy" },
  { "extract", cmd_extract, "extract [-f filter] file [tag...]", "\
Options:\n\
\n\
-f, --filter=FILT       Only extract key components matching FILT.\n\
" },
  { "merge", cmd_merge, "merge file" },
  { 0, 0, 0 }
};

typedef struct cmd cmd;

/*----- Main code ---------------------------------------------------------*/

/* --- @findcmd@ --- *
 *
 * Arguments:   @const char *name@ = a command name
 *
 * Returns:     Pointer to the command structure.
 *
 * Use:         Looks up a command by name.  If the command isn't found, an
 *              error is reported and the program is terminated.
 */

static cmd *findcmd(const char *name)
{
  cmd *c, *chosen = 0;
  size_t sz = strlen(name);

  for (c = cmds; c->name; c++) {
    if (strncmp(name, c->name, sz) == 0) {
      if (c->name[sz] == 0) {
        chosen = c;
        break;
      } else if (chosen)
        die(EXIT_FAILURE, "ambiguous command name `%s'", name);
      else
        chosen = c;
    }
  }
  if (!chosen)
    die(EXIT_FAILURE, "unknown command name `%s'", name);
  return (chosen);
}

/* --- Helpful GNUy functions --- */

void usage(FILE *fp)
{
  pquis(fp, "Usage: $ [-k keyring] command [args]\n");
}

void version(FILE *fp)
{
  pquis(fp, "$, Catacomb version " VERSION "\n");
}

void help(FILE *fp, char **argv)
{
  cmd *c;

  version(fp);
  fputc('\n', fp);
  if (*argv) {
    c = findcmd(*argv);
    fprintf(fp, "Usage: %s [-k keyring] %s\n", QUIS, c->usage);
    if (c->help) {
      fputc('\n', fp);  
      fputs(c->help, fp);
    }
  } else {
    usage(fp);
    fputs("\n\
Performs various simple key management operations.  Command line options\n\
recognized are:\n\
\n\
-h, --help [COMMAND]    Display this help text (or help for COMMAND).\n\
-v, --version           Display version number.\n\
-u, --usage             Display short usage summary.\n\
\n\
-k, --keyring=FILE      Read and write keys in FILE.\n\
-i, --id=TAG            Use key TAG for random number generator.\n\
-t, --type=TYPE         Use key TYPE for random number generator.\n\
\n\
The following commands are understood:\n\n",
          fp);
    for (c = cmds; c->name; c++)
      fprintf(fp, "%s\n", c->usage);
  }
}

/* --- @main@ --- *
 *
 * Arguments:   @int argc@ = number of command line arguments
 *              @char *argv[]@ = array of command line arguments
 *
 * Returns:     Nonzero on failure.
 *
 * Use:         Main program.  Performs simple key management functions.
 */

int main(int argc, char *argv[])
{
  unsigned f = 0;

#define f_bogus 1u

  /* --- Initialization --- */

  ego(argv[0]);
  sub_init();

  /* --- Parse command line options --- */

  for (;;) {
    static struct option opt[] = {

      /* --- Standard GNUy help options --- */

      { "help",         0,              0,      'h' },
      { "version",      0,              0,      'v' },
      { "usage",        0,              0,      'u' },

      /* --- Real live useful options --- */

      { "keyring",      OPTF_ARGREQ,    0,      'k' },

      /* --- Magic terminator --- */

      { 0,              0,              0,      0 }
    };
    int i = mdwopt(argc, argv, "+hvu k:", opt, 0, 0, 0);

    if (i < 0)
      break;
    switch (i) {

      /* --- GNU help options --- */

      case 'h':
        help(stdout, argv + optind);
        exit(0);
      case 'v':
        version(stdout);
        exit(0);
      case 'u':
        usage(stdout);
        exit(0);

      /* --- Real useful options --- */

      case 'k':
        keyfile = optarg;
        break;

      /* --- Bogosity --- */

      default:
        f |= f_bogus;
        break;
    }
  }

  /* --- Complain about excessive bogons --- */

  if (f & f_bogus || optind == argc) {
    usage(stderr);
    exit(1);
  }

  /* --- Initialize the Catacomb random number generator --- */

  rand_noisesrc(RAND_GLOBAL, &noise_source);
  rand_seed(RAND_GLOBAL, 160);

  /* --- Dispatch to appropriate command handler --- */

  argc -= optind;
  argv += optind;
  optind = 0;
  return (findcmd(argv[0])->cmd(argc, argv));
}

/*----- That's all, folks -------------------------------------------------*/