g10/keyid.c

   1 /* keyid.c - key ID and fingerprint handling
   2  * Copyright (C) 1998, 1999, 2000, 2001, 2003,
   3  *               2004, 2006 Free Software Foundation, Inc.
   4  *
   5  * This file is part of GnuPG.
   6  *
   7  * GnuPG is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * GnuPG is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <config.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <errno.h>
  26 #include <time.h>
  27 #include <assert.h>
  28
  29 #include "gpg.h"
  30 #include "util.h"
  31 #include "main.h"
  32 #include "packet.h"
  33 #include "options.h"
  34 #include "keydb.h"
  35 #include "i18n.h"
  36 #include "rmd160.h"
  37
  38 int
  39 pubkey_letter( int algo )
  40 {
  41     switch( algo ) {
  42       case PUBKEY_ALGO_RSA:     return 'R' ;
  43       case PUBKEY_ALGO_RSA_E:   return 'r' ;
  44       case PUBKEY_ALGO_RSA_S:   return 's' ;
  45       case PUBKEY_ALGO_ELGAMAL_E: return 'g';
  46       case PUBKEY_ALGO_ELGAMAL: return 'G' ;
  47       case PUBKEY_ALGO_DSA:     return 'D' ;
  48       default: return '?';
  49     }
  50 }
  51
  52 /* This function is useful for v4 fingerprints and v3 or v4 key
  53    signing. */
  54 void
  55 hash_public_key( gcry_md_hd_t md, PKT_public_key *pk )
  56 {
  57   unsigned int n = 6;
  58   unsigned int nn[PUBKEY_MAX_NPKEY];
  59   byte *pp[PUBKEY_MAX_NPKEY];
  60   int i;
  61   unsigned int nbits;
  62   size_t nbytes;
  63   int npkey = pubkey_get_npkey (pk->pubkey_algo);
  64
  65   /* Two extra bytes for the expiration date in v3 */
  66   if(pk->version<4)
  67     n+=2;
  68
  69   if (npkey==0 && pk->pkey[0]
  70       && gcry_mpi_get_flag (pk->pkey[0], GCRYMPI_FLAG_OPAQUE))
  71     {
  72       pp[0] = gcry_mpi_get_opaque (pk->pkey[0], &nbits);
  73       nn[0] = (nbits+7)/8;
  74       n+=nn[0];
  75     }
  76   else
  77     for(i=0; i < npkey; i++ )
  78       {
  79         if (gcry_mpi_print (GCRYMPI_FMT_PGP, NULL, 0, &nbytes, pk->pkey[i]))
  80           BUG ();
  81         pp[i] = xmalloc (nbytes);
  82         if (gcry_mpi_print (GCRYMPI_FMT_PGP, pp[i], nbytes,
  83                             &nbytes, pk->pkey[i]))
  84           BUG ();
  85         nn[i] = nbytes;
  86         n += nn[i];
  87       }
  88
  89   gcry_md_putc ( md, 0x99 );     /* ctb */
  90   /* What does it mean if n is greater than than 0xFFFF ? */
  91   gcry_md_putc ( md, n >> 8 );   /* 2 byte length header */
  92   gcry_md_putc ( md, n );
  93   gcry_md_putc ( md, pk->version );
  94
  95   gcry_md_putc ( md, pk->timestamp >> 24 );
  96   gcry_md_putc ( md, pk->timestamp >> 16 );
  97   gcry_md_putc ( md, pk->timestamp >>  8 );
  98   gcry_md_putc ( md, pk->timestamp       );
  99
 100   if(pk->version<4)
 101     {
 102       u16 days=0;
 103       if(pk->expiredate)
 104         days=(u16)((pk->expiredate - pk->timestamp) / 86400L);
 105
 106       gcry_md_putc ( md, days >> 8 );
 107       gcry_md_putc ( md, days );
 108     }
 109
 110   gcry_md_putc ( md, pk->pubkey_algo );
 111
 112   if(npkey==0 && pk->pkey[0]
 113      && gcry_mpi_get_flag (pk->pkey[0], GCRYMPI_FLAG_OPAQUE))
 114     {
 115       gcry_md_write (md, pp[0], nn[0]);
 116     }
 117   else
 118     for(i=0; i < npkey; i++ )
 119       {
 120         gcry_md_write ( md, pp[i], nn[i] );
 121         xfree(pp[i]);
 122       }
 123 }
 124
 125 static gcry_md_hd_t
 126 do_fingerprint_md( PKT_public_key *pk )
 127 {
 128   gcry_md_hd_t md;
 129
 130   if (gcry_md_open (&md, DIGEST_ALGO_SHA1, 0))
 131     BUG ();
 132   hash_public_key(md,pk);
 133   gcry_md_final( md );
 134
 135   return md;
 136 }
 137
 138 static gcry_md_hd_t
 139 do_fingerprint_md_sk( PKT_secret_key *sk )
 140 {
 141     PKT_public_key pk;
 142     int npkey = pubkey_get_npkey( sk->pubkey_algo ); /* npkey is correct! */
 143     int i;
 144
 145     if(npkey==0)
 146       return NULL;
 147
 148     pk.pubkey_algo = sk->pubkey_algo;
 149     pk.version     = sk->version;
 150     pk.timestamp = sk->timestamp;
 151     pk.expiredate = sk->expiredate;
 152     pk.pubkey_algo = sk->pubkey_algo;
 153     for( i=0; i < npkey; i++ )
 154       pk.pkey[i] = sk->skey[i];
 155     return do_fingerprint_md( &pk );
 156 }
 157
 158
 159 u32
 160 v3_keyid (gcry_mpi_t a, u32 *ki)
 161 {
 162   byte *buffer, *p;
 163   size_t nbytes;
 164
 165   if (gcry_mpi_print (GCRYMPI_FMT_USG, NULL, 0, &nbytes, a ))
 166     BUG ();
 167   /* fixme: allocate it on the stack */
 168   buffer = xmalloc (nbytes);
 169   if (gcry_mpi_print( GCRYMPI_FMT_USG, buffer, nbytes, NULL, a ))
 170     BUG ();
 171   if (nbytes < 8) /* oops */
 172     ki[0] = ki[1] = 0;
 173   else
 174     {
 175       p = buffer + nbytes - 8;
 176       ki[0] = (p[0] << 24) | (p[1] <<16) | (p[2] << 8) | p[3];
 177       p += 4;
 178       ki[1] = (p[0] << 24) | (p[1] <<16) | (p[2] << 8) | p[3];
 179     }
 180   xfree (buffer);
 181   return ki[1];
 182 }
 183
 184
 185 size_t
 186 keystrlen(void)
 187 {
 188   switch(opt.keyid_format)
 189     {
 190     case KF_SHORT:
 191       return 8;
 192
 193     case KF_LONG:
 194       return 16;
 195
 196     case KF_0xSHORT:
 197       return 10;
 198
 199     case KF_0xLONG:
 200       return 18;
 201
 202     default:
 203       BUG();
 204     }
 205 }
 206
 207 const char *
 208 keystr(u32 *keyid)
 209 {
 210   static char keyid_str[19];
 211
 212   switch(opt.keyid_format)
 213     {
 214     case KF_SHORT:
 215       sprintf(keyid_str,"%08lX",(ulong)keyid[1]);
 216       break;
 217
 218     case KF_LONG:
 219       if(keyid[0])
 220         sprintf(keyid_str,"%08lX%08lX",(ulong)keyid[0],(ulong)keyid[1]);
 221       else
 222         sprintf(keyid_str,"%08lX",(ulong)keyid[1]);
 223       break;
 224
 225     case KF_0xSHORT:
 226       sprintf(keyid_str,"0x%08lX",(ulong)keyid[1]);
 227       break;
 228
 229     case KF_0xLONG:
 230       if(keyid[0])
 231         sprintf(keyid_str,"0x%08lX%08lX",(ulong)keyid[0],(ulong)keyid[1]);
 232       else
 233         sprintf(keyid_str,"0x%08lX",(ulong)keyid[1]);
 234       break;
 235
 236     default:
 237       BUG();
 238     }
 239
 240   return keyid_str;
 241 }
 242
 243 const char *
 244 keystr_from_pk(PKT_public_key *pk)
 245 {
 246   keyid_from_pk(pk,NULL);
 247
 248   return keystr(pk->keyid);
 249 }
 250
 251 const char *
 252 keystr_from_sk(PKT_secret_key *sk)
 253 {
 254   keyid_from_sk(sk,NULL);
 255
 256   return keystr(sk->keyid);
 257 }
 258
 259 const char *
 260 keystr_from_desc(KEYDB_SEARCH_DESC *desc)
 261 {
 262   switch(desc->mode)
 263     {
 264     case KEYDB_SEARCH_MODE_LONG_KID:
 265     case KEYDB_SEARCH_MODE_SHORT_KID:
 266       return keystr(desc->u.kid);
 267
 268     case KEYDB_SEARCH_MODE_FPR20:
 269       {
 270         u32 keyid[2];
 271
 272         keyid[0] = ((unsigned char)desc->u.fpr[12] << 24
 273                     | (unsigned char)desc->u.fpr[13] << 16
 274                     | (unsigned char)desc->u.fpr[14] << 8
 275                     | (unsigned char)desc->u.fpr[15]);
 276         keyid[1] = ((unsigned char)desc->u.fpr[16] << 24
 277                     | (unsigned char)desc->u.fpr[17] << 16
 278                     | (unsigned char)desc->u.fpr[18] << 8
 279                     | (unsigned char)desc->u.fpr[19]);
 280
 281         return keystr(keyid);
 282       }
 283
 284     case KEYDB_SEARCH_MODE_FPR16:
 285       return "?v3 fpr?";
 286
 287     default:
 288       BUG();
 289     }
 290 }
 291
 292 /****************
 293  * Get the keyid from the secret key and put it into keyid
 294  * if this is not NULL. Return the 32 low bits of the keyid.
 295  */
 296 u32
 297 keyid_from_sk( PKT_secret_key *sk, u32 *keyid )
 298 {
 299   u32 lowbits;
 300   u32 dummy_keyid[2];
 301
 302   if( !keyid )
 303     keyid = dummy_keyid;
 304
 305   if( sk->keyid[0] || sk->keyid[1] )
 306     {
 307       keyid[0] = sk->keyid[0];
 308       keyid[1] = sk->keyid[1];
 309       lowbits = keyid[1];
 310     }
 311   else if( sk->version < 4 )
 312     {
 313       if( is_RSA(sk->pubkey_algo) )
 314         {
 315           lowbits = (pubkey_get_npkey (sk->pubkey_algo) ?
 316                      v3_keyid( sk->skey[0], keyid ) : 0); /* Take n. */
 317           sk->keyid[0]=keyid[0];
 318           sk->keyid[1]=keyid[1];
 319         }
 320       else
 321         sk->keyid[0]=sk->keyid[1]=keyid[0]=keyid[1]=lowbits=0xFFFFFFFF;
 322     }
 323   else
 324     {
 325       const byte *dp;
 326       gcry_md_hd_t md;
 327
 328       md = do_fingerprint_md_sk(sk);
 329       if(md)
 330         {
 331           dp = gcry_md_read (md, 0);
 332           keyid[0] = dp[12] << 24 | dp[13] << 16 | dp[14] << 8 | dp[15] ;
 333           keyid[1] = dp[16] << 24 | dp[17] << 16 | dp[18] << 8 | dp[19] ;
 334           lowbits = keyid[1];
 335           gcry_md_close (md);
 336           sk->keyid[0] = keyid[0];
 337           sk->keyid[1] = keyid[1];
 338         }
 339       else
 340         sk->keyid[0]=sk->keyid[1]=keyid[0]=keyid[1]=lowbits=0xFFFFFFFF;
 341     }
 342
 343   return lowbits;
 344 }
 345
 346
 347 /****************
 348  * Get the keyid from the public key and put it into keyid
 349  * if this is not NULL. Return the 32 low bits of the keyid.
 350  */
 351 u32
 352 keyid_from_pk( PKT_public_key *pk, u32 *keyid )
 353 {
 354   u32 lowbits;
 355   u32 dummy_keyid[2];
 356
 357   if( !keyid )
 358     keyid = dummy_keyid;
 359
 360   if( pk->keyid[0] || pk->keyid[1] )
 361     {
 362       keyid[0] = pk->keyid[0];
 363       keyid[1] = pk->keyid[1];
 364       lowbits = keyid[1];
 365     }
 366   else if( pk->version < 4 )
 367     {
 368       if( is_RSA(pk->pubkey_algo) )
 369         {
 370           lowbits = (pubkey_get_npkey (pk->pubkey_algo) ?
 371                      v3_keyid ( pk->pkey[0], keyid ) : 0); /* From n. */
 372           pk->keyid[0] = keyid[0];
 373           pk->keyid[1] = keyid[1];
 374         }
 375       else
 376         pk->keyid[0]=pk->keyid[1]=keyid[0]=keyid[1]=lowbits=0xFFFFFFFF;
 377     }
 378   else
 379     {
 380       const byte *dp;
 381       gcry_md_hd_t md;
 382
 383       md = do_fingerprint_md(pk);
 384       if(md)
 385         {
 386           dp = gcry_md_read ( md, 0 );
 387           keyid[0] = dp[12] << 24 | dp[13] << 16 | dp[14] << 8 | dp[15] ;
 388           keyid[1] = dp[16] << 24 | dp[17] << 16 | dp[18] << 8 | dp[19] ;
 389           lowbits = keyid[1];
 390           gcry_md_close (md);
 391           pk->keyid[0] = keyid[0];
 392           pk->keyid[1] = keyid[1];
 393         }
 394       else
 395         pk->keyid[0]=pk->keyid[1]=keyid[0]=keyid[1]=lowbits=0xFFFFFFFF;
 396     }
 397
 398   return lowbits;
 399 }
 400
 401
 402 /****************
 403  * Get the keyid from the fingerprint.  This function is simple for most
 404  * keys, but has to do a keylookup for old stayle keys.
 405  */
 406 u32
 407 keyid_from_fingerprint( const byte *fprint, size_t fprint_len, u32 *keyid )
 408 {
 409     u32 dummy_keyid[2];
 410
 411     if( !keyid )
 412         keyid = dummy_keyid;
 413
 414     if( fprint_len != 20 ) {
 415         /* This is special as we have to lookup the key first */
 416         PKT_public_key pk;
 417         int rc;
 418
 419         memset( &pk, 0, sizeof pk );
 420         rc = get_pubkey_byfprint( &pk, fprint, fprint_len );
 421         if( rc ) {
 422             log_error("Oops: keyid_from_fingerprint: no pubkey\n");
 423             keyid[0] = 0;
 424             keyid[1] = 0;
 425         }
 426         else
 427             keyid_from_pk( &pk, keyid );
 428     }
 429     else {
 430         const byte *dp = fprint;
 431         keyid[0] = dp[12] << 24 | dp[13] << 16 | dp[14] << 8 | dp[15] ;
 432         keyid[1] = dp[16] << 24 | dp[17] << 16 | dp[18] << 8 | dp[19] ;
 433     }
 434
 435     return keyid[1];
 436 }
 437
 438
 439 u32
 440 keyid_from_sig( PKT_signature *sig, u32 *keyid )
 441 {
 442     if( keyid ) {
 443         keyid[0] = sig->keyid[0];
 444         keyid[1] = sig->keyid[1];
 445     }
 446     return sig->keyid[1];
 447 }
 448
 449 byte *
 450 namehash_from_uid(PKT_user_id *uid)
 451 {
 452   if (!uid->namehash)
 453     {
 454       uid->namehash = xmalloc (20);
 455
 456       if(uid->attrib_data)
 457         rmd160_hash_buffer (uid->namehash, uid->attrib_data, uid->attrib_len);
 458       else
 459         rmd160_hash_buffer (uid->namehash, uid->name, uid->len);
 460     }
 461
 462   return uid->namehash;
 463 }
 464
 465 /****************
 466  * return the number of bits used in the pk
 467  */
 468 unsigned
 469 nbits_from_pk( PKT_public_key *pk )
 470 {
 471     return pubkey_nbits( pk->pubkey_algo, pk->pkey );
 472 }
 473
 474 /****************
 475  * return the number of bits used in the sk
 476  */
 477 unsigned
 478 nbits_from_sk( PKT_secret_key *sk )
 479 {
 480     return pubkey_nbits( sk->pubkey_algo, sk->skey );
 481 }
 482
 483 static const char *
 484 mk_datestr (char *buffer, time_t atime)
 485 {
 486     struct tm *tp;
 487
 488     if ( atime < 0 ) /* 32 bit time_t and after 2038-01-19 */
 489         strcpy (buffer, "????" "-??" "-??"); /* mark this as invalid */
 490     else {
 491         tp = gmtime (&atime);
 492         sprintf (buffer,"%04d-%02d-%02d",
 493                  1900+tp->tm_year, tp->tm_mon+1, tp->tm_mday );
 494     }
 495     return buffer;
 496 }
 497
 498 /****************
 499  * return a string with the creation date of the pk
 500  * Note: this is alloced in a static buffer.
 501  *    Format is: yyyy-mm-dd
 502  */
 503 const char *
 504 datestr_from_pk( PKT_public_key *pk )
 505 {
 506     static char buffer[11+5];
 507     time_t atime = pk->timestamp;
 508
 509     return mk_datestr (buffer, atime);
 510 }
 511
 512 const char *
 513 datestr_from_sk( PKT_secret_key *sk )
 514 {
 515     static char buffer[11+5];
 516     time_t atime = sk->timestamp;
 517
 518     return mk_datestr (buffer, atime);
 519 }
 520
 521 const char *
 522 datestr_from_sig( PKT_signature *sig )
 523 {
 524     static char buffer[11+5];
 525     time_t atime = sig->timestamp;
 526
 527     return mk_datestr (buffer, atime);
 528 }
 529
 530 const char *
 531 expirestr_from_pk( PKT_public_key *pk )
 532 {
 533     static char buffer[11+5];
 534     time_t atime;
 535
 536     if( !pk->expiredate )
 537         return _("never     ");
 538     atime = pk->expiredate;
 539     return mk_datestr (buffer, atime);
 540 }
 541
 542 const char *
 543 expirestr_from_sk( PKT_secret_key *sk )
 544 {
 545     static char buffer[11+5];
 546     time_t atime;
 547
 548     if( !sk->expiredate )
 549         return _("never     ");
 550     atime = sk->expiredate;
 551     return mk_datestr (buffer, atime);
 552 }
 553
 554 const char *
 555 expirestr_from_sig( PKT_signature *sig )
 556 {
 557     static char buffer[11+5];
 558     time_t atime;
 559
 560     if(!sig->expiredate)
 561       return _("never     ");
 562     atime=sig->expiredate;
 563     return mk_datestr (buffer, atime);
 564 }
 565
 566 const char *
 567 revokestr_from_pk( PKT_public_key *pk )
 568 {
 569     static char buffer[11+5];
 570     time_t atime;
 571
 572     if(!pk->revoked.date)
 573       return _("never     ");
 574     atime=pk->revoked.date;
 575     return mk_datestr (buffer, atime);
 576 }
 577
 578
 579 const char *
 580 usagestr_from_pk( PKT_public_key *pk )
 581 {
 582   static char buffer[10];
 583   int i = 0;
 584   unsigned int use = pk->pubkey_usage;
 585
 586   if ( use & PUBKEY_USAGE_SIG )
 587     buffer[i++] = 'S';
 588
 589   if ( use & PUBKEY_USAGE_CERT )
 590     buffer[i++] = 'C';
 591
 592   if ( use & PUBKEY_USAGE_ENC )
 593     buffer[i++] = 'E';
 594
 595   if ( (use & PUBKEY_USAGE_AUTH) )
 596     buffer[i++] = 'A';
 597
 598   while (i < 4)
 599     buffer[i++] = ' ';
 600
 601   buffer[i] = 0;
 602   return buffer;
 603 }
 604
 605
 606 const char *
 607 colon_strtime (u32 t)
 608 {
 609   static char buf[20];
 610
 611   if (!t)
 612     return "";
 613   snprintf (buf, sizeof buf, "%lu", (ulong)t);
 614   return buf;
 615 }
 616
 617 const char *
 618 colon_datestr_from_pk (PKT_public_key *pk)
 619 {
 620   static char buf[20];
 621
 622   snprintf (buf, sizeof buf, "%lu", (ulong)pk->timestamp);
 623   return buf;
 624 }
 625
 626 const char *
 627 colon_datestr_from_sk (PKT_secret_key *sk)
 628 {
 629   static char buf[20];
 630
 631   snprintf (buf, sizeof buf, "%lu", (ulong)sk->timestamp);
 632   return buf;
 633 }
 634
 635 const char *
 636 colon_datestr_from_sig (PKT_signature *sig)
 637 {
 638   static char buf[20];
 639
 640   snprintf (buf, sizeof buf, "%lu", (ulong)sig->timestamp);
 641   return buf;
 642 }
 643
 644 const char *
 645 colon_expirestr_from_sig (PKT_signature *sig)
 646 {
 647   static char buf[20];
 648
 649   if (!sig->expiredate)
 650     return "";
 651
 652   snprintf (buf, sizeof buf,"%lu", (ulong)sig->expiredate);
 653   return buf;
 654 }
 655
 656
 657 /**************** .
 658  * Return a byte array with the fingerprint for the given PK/SK
 659  * The length of the array is returned in ret_len. Caller must free
 660  * the array or provide an array of length MAX_FINGERPRINT_LEN.
 661  */
 662
 663 byte *
 664 fingerprint_from_pk( PKT_public_key *pk, byte *array, size_t *ret_len )
 665 {
 666   byte *buf;
 667   const byte *dp;
 668   size_t len, nbytes;
 669   int i;
 670
 671   if ( pk->version < 4 )
 672     {
 673       if ( is_RSA(pk->pubkey_algo) )
 674         {
 675           /* RSA in version 3 packets is special. */
 676           gcry_md_hd_t md;
 677
 678           if (gcry_md_open (&md, DIGEST_ALGO_MD5, 0))
 679             BUG ();
 680           if ( pubkey_get_npkey (pk->pubkey_algo) > 1 )
 681             {
 682               for (i=0; i < 2; i++)
 683                 {
 684                   if (gcry_mpi_print (GCRYMPI_FMT_USG, NULL, 0,
 685                                       &nbytes, pk->pkey[i]))
 686                     BUG ();
 687                   /* fixme: Better allocate BUF on the stack */
 688                   buf = xmalloc (nbytes);
 689                   if (gcry_mpi_print (GCRYMPI_FMT_USG, buf, nbytes,
 690                                       NULL, pk->pkey[i]))
 691                     BUG ();
 692                   gcry_md_write (md, buf, nbytes);
 693                   xfree (buf);
 694                 }
 695             }
 696           gcry_md_final (md);
 697           if (!array)
 698             array = xmalloc (16);
 699           len = 16;
 700           memcpy (array, gcry_md_read (md, DIGEST_ALGO_MD5), 16);
 701           gcry_md_close(md);
 702         }
 703       else
 704         {
 705           if (!array)
 706             array = xmalloc(16);
 707           len = 16;
 708           memset (array,0,16);
 709         }
 710     }
 711   else
 712     {
 713       gcry_md_hd_t md;
 714
 715       md = do_fingerprint_md(pk);
 716       dp = gcry_md_read( md, 0 );
 717       len = gcry_md_get_algo_dlen (gcry_md_get_algo (md));
 718       assert( len <= MAX_FINGERPRINT_LEN );
 719       if (!array)
 720         array = xmalloc ( len );
 721       memcpy (array, dp, len );
 722       pk->keyid[0] = dp[12] << 24 | dp[13] << 16 | dp[14] << 8 | dp[15] ;
 723       pk->keyid[1] = dp[16] << 24 | dp[17] << 16 | dp[18] << 8 | dp[19] ;
 724       gcry_md_close( md);
 725     }
 726
 727   *ret_len = len;
 728   return array;
 729 }
 730
 731 byte *
 732 fingerprint_from_sk( PKT_secret_key *sk, byte *array, size_t *ret_len )
 733 {
 734   byte *buf;
 735   const char *dp;
 736   size_t len, nbytes;
 737   int i;
 738
 739   if (sk->version < 4)
 740     {
 741       if ( is_RSA(sk->pubkey_algo) )
 742         {
 743           /* RSA in version 3 packets is special. */
 744           gcry_md_hd_t md;
 745
 746           if (gcry_md_open (&md, DIGEST_ALGO_MD5, 0))
 747             BUG ();
 748           if (pubkey_get_npkey( sk->pubkey_algo ) > 1)
 749             {
 750               for (i=0; i < 2; i++)
 751                 {
 752                   if (gcry_mpi_print (GCRYMPI_FMT_USG, NULL, 0,
 753                                       &nbytes, sk->skey[i]))
 754                     BUG ();
 755                   /* fixme: Better allocate BUF on the stack */
 756                   buf = xmalloc (nbytes);
 757                   if (gcry_mpi_print (GCRYMPI_FMT_USG, buf, nbytes,
 758                                       NULL, sk->skey[i]))
 759                     BUG ();
 760                   gcry_md_write (md, buf, nbytes);
 761                   xfree (buf);
 762                 }
 763             }
 764           gcry_md_final(md);
 765           if (!array)
 766             array = xmalloc (16);
 767           len = 16;
 768           memcpy (array, gcry_md_read (md, DIGEST_ALGO_MD5), 16);
 769           gcry_md_close (md);
 770         }
 771       else
 772         {
 773           if (!array)
 774             array = xmalloc (16);
 775           len=16;
 776           memset (array,0,16);
 777         }
 778     }
 779   else
 780     {
 781       gcry_md_hd_t md;
 782
 783       md = do_fingerprint_md_sk(sk);
 784       if (md)
 785         {
 786           dp = gcry_md_read ( md, 0 );
 787           len = gcry_md_get_algo_dlen ( gcry_md_get_algo (md) );
 788           assert ( len <= MAX_FINGERPRINT_LEN );
 789           if (!array)
 790             array = xmalloc( len );
 791           memcpy (array, dp, len);
 792           gcry_md_close (md);
 793         }
 794       else
 795         {
 796           len = MAX_FINGERPRINT_LEN;
 797           if (!array)
 798             array = xmalloc (len);
 799           memset (array, 0, len);
 800         }
 801     }
 802
 803   *ret_len = len;
 804   return array;
 805 }
 806
 807
 808 /* Create a serialno/fpr string from the serial number and the secret
 809    key.  Caller must free the returned string.  There is no error
 810    return.  */
 811 char *
 812 serialno_and_fpr_from_sk (const unsigned char *sn, size_t snlen,
 813                           PKT_secret_key *sk)
 814 {
 815   unsigned char fpr[MAX_FINGERPRINT_LEN];
 816   size_t fprlen;
 817   char *buffer, *p;
 818   int i;
 819
 820   fingerprint_from_sk (sk, fpr, &fprlen);
 821   buffer = p = xmalloc (snlen*2 + 1 + fprlen*2 + 1);
 822   for (i=0; i < snlen; i++, p+=2)
 823     sprintf (p, "%02X", sn[i]);
 824   *p++ = '/';
 825   for (i=0; i < fprlen; i++, p+=2)
 826     sprintf (p, "%02X", fpr[i]);
 827   *p = 0;
 828   return buffer;
 829 }
 830