See ChangeLog: Mon Apr 26 17:48:15 CEST 1999 Werner Koch

32 files changed, 866 insertions, 265 deletions

diff --git a/NEWS b/NEWS
index 073e82ec2..624973263 100644
--- a/NEWS
+++ b/NEWS
@@ -8,6 +8,9 @@
 
     * Merged gpgm and gpg into one binary.
 
+    * Add revsig command to the edit menu.  It is now possible to
+      revoke signature.
+
 
 Noteworthy changes in version 0.9.5
 -----------------------------------
diff --git a/PROJECTS b/PROJECTS
index c5c445893..a794148c3 100644
--- a/PROJECTS
+++ b/PROJECTS
@@ -47,3 +47,7 @@
 
     * Keep a list of duplicate, faked or unwanted keyids.
 
+    * The current code has knowledge about the structure of a keyblock.
+      We should add an abstraction layer so that adding support for
+      different certificate structures will become easier.
+
diff --git a/TODO b/TODO
index 2285a49ce..aa736aee2 100644
--- a/TODO
+++ b/TODO
@@ -8,7 +8,7 @@
 
   * See why we always get this "Hmmm, public key not anymore available"
 
-  * print a warning when a revoked/expired secret key is used.
+  * print a warning when a revoked/expired _secret_ key is used.
 
   * remove more "Fixmes"
 
diff --git a/doc/gpg.1pod b/doc/gpg.1pod
index 42d4298bf..95f5c301f 100644
--- a/doc/gpg.1pod
+++ b/doc/gpg.1pod
@@ -473,6 +473,11 @@ B<--force-v3-sigs>
     on key material.  This options forces v3 signatures for
     signatures on data.
 
+B<--force-mdc>
+    Force the use of encryption with appended manipulation
+    code.  This is always used with the newer cipher (those
+    with a blocksize greater than 64 bit).
+
 B<--lock-once>
     Lock the file the first time a lock is requested
     and do not release the lock until the process
diff --git a/doc/manual.sgml b/doc/manual.sgml
index 2d02caae4..a604d5357 100644
--- a/doc/manual.sgml
+++ b/doc/manual.sgml
@@ -5,7 +5,7 @@
     <title>The GNU Privacy Guard</title>
     <authorgroup>
       <author> <firstname>Werner</firstname> <surname>Koch</surname>
-	<affiliation><address><email>wk@computer.org</email></address>
+	<affiliation><address><email>wk@gnupg.org</email></address>
 	</affiliation>
       </author>
     </authorgroup>
diff --git a/g10/ChangeLog b/g10/ChangeLog
index 90f7f9209..739677029 100644
--- a/g10/ChangeLog
+++ b/g10/ChangeLog
@@ -1,3 +1,16 @@
+Mon Apr 26 17:48:15 CEST 1999  Werner Koch  <wk@isil.d.shuttle.de>
+
+	* parse-packet.c (parse_signature): Add the MDC hack.
+	* build-packet.c (do_signature): Ditto.
+	* free-packet.c (free_seckey_enc,copy_signature,cmp_signatures): Ditto.
+	* mainproc.c (do_check_sig): Ditto.
+	* sig-check.c (mdc_kludge_check): New.
+	* encode.c (encrypt_mdc_file): New.
+
+	* keyedit.c (check_all_keysigs): List revocations.
+	* (menu_revsig): New.
+	* sign (make_keysig_packet): Support for class 0x30.
+
 Sun Apr 18 20:48:15 CEST 1999  Werner Koch  <wk@isil.d.shuttle.de>
 
 	* pkclist.c (select_algo_from_prefs): Fixed the case that one key
@@ -7,7 +20,6 @@ Sun Apr 18 20:48:15 CEST 1999  Werner Koch  <wk@isil.d.shuttle.de>
 
 Sun Apr 18 10:11:28 CEST 1999  Werner Koch  <wk@isil.d.shuttle.de>
 
-
 	* seckey-cert.c (do_check): Use real IV instead of a 0 one, so that
 	it works even if the length of the IV doesn't match the blocksize.
 	Removed the save_iv stuff.
diff --git a/g10/build-packet.c b/g10/build-packet.c
index b3831eb32..285f115f4 100644
--- a/g10/build-packet.c
+++ b/g10/build-packet.c
@@ -728,9 +728,15 @@ do_signature( IOBUF out, int ctb, PKT_signature *sig )
     }
     iobuf_put(a, sig->digest_start[0] );
     iobuf_put(a, sig->digest_start[1] );
-    n = pubkey_get_nsig( sig->pubkey_algo );
-    if( !n )
-	write_fake_data( a, sig->data[0] );
+    n = sig->pubkey_algo? pubkey_get_nsig( sig->pubkey_algo ) : 0;
+    if( !n ) {	/* the MDC data */
+	fputs("The MDC: ", stderr);
+	mpi_print(stderr, sig->data[0], 0 );
+	fputs("  ", stderr);
+	mpi_print(stderr, sig->data[0], 1 );
+	putc('\n', stderr);
+	mpi_write( a, sig->data[0] );
+    }
     for(i=0; i < n; i++ )
 	mpi_write(a, sig->data[i] );
 
diff --git a/g10/compress.c b/g10/compress.c
index accca02cc..5ad4a27de 100644
--- a/g10/compress.c
+++ b/g10/compress.c
@@ -256,7 +256,7 @@ compress_filter( void *opaque, int control,
  * Handle a compressed packet
  */
 int
-handle_compressed( PKT_compressed *cd,
+handle_compressed( void *procctx, PKT_compressed *cd,
 		   int (*callback)(IOBUF, void *), void *passthru )
 {
     compress_filter_context_t cfx;
@@ -271,7 +271,7 @@ handle_compressed( PKT_compressed *cd,
     if( callback )
 	rc = callback(cd->buf, passthru );
     else
-	rc = proc_packets(cd->buf);
+	rc = proc_packets(procctx, cd->buf);
   #if 0
     iobuf_pop_filter( cd->buf, compress_filter, &cfx );
     if( cd->len )
diff --git a/g10/decrypt.c b/g10/decrypt.c
index 3d223eadd..df6b0a7c0 100644
--- a/g10/decrypt.c
+++ b/g10/decrypt.c
@@ -71,7 +71,7 @@ decrypt_message( const char *filename )
 	no_out = 1;
 	opt.outfile = "-";
     }
-    rc = proc_encryption_packets( fp );
+    rc = proc_encryption_packets( NULL, fp );
     if( no_out )
        opt.outfile = NULL;
     iobuf_close(fp);
diff --git a/g10/encode.c b/g10/encode.c
index 825a4c98a..ba97299e2 100644
--- a/g10/encode.c
+++ b/g10/encode.c
@@ -39,6 +39,7 @@
 
 
 static int encode_simple( const char *filename, int mode );
+static int encode_crypt_mdc( const char* fname, STRLIST remusr );
 static int write_pubkey_enc_from_list( PK_LIST pk_list, DEK *dek, IOBUF out );
 
 
@@ -215,6 +216,10 @@ encode_crypt( const char *filename, STRLIST remusr )
     PK_LIST pk_list;
     int do_compress = opt.compress && !opt.rfc1991;
 
+    if( opt.force_mdc )
+	return encode_crypt_mdc( filename, remusr );
+
+
     memset( &cfx, 0, sizeof cfx);
     memset( &afx, 0, sizeof afx);
     memset( &zfx, 0, sizeof zfx);
@@ -329,6 +334,193 @@ encode_crypt( const char *filename, STRLIST remusr )
 }
 
 
+
+static int
+encode_crypt_mdc( const char* fname, STRLIST remusr )
+{
+    armor_filter_context_t afx;
+    compress_filter_context_t zfx;
+    md_filter_context_t mfx;
+    text_filter_context_t tfx;
+    encrypt_filter_context_t efx;
+    IOBUF inp = NULL, out = NULL;
+    PACKET pkt;
+    PKT_plaintext *pt = NULL;
+    u32 filesize;
+    int rc = 0;
+    PK_LIST pk_list = NULL;
+    int compr_algo = -1; /* unknown */
+
+
+    memset( &afx, 0, sizeof afx);
+    memset( &zfx, 0, sizeof zfx);
+    memset( &mfx, 0, sizeof mfx);
+    memset( &tfx, 0, sizeof tfx);
+    memset( &efx, 0, sizeof efx);
+    init_packet( &pkt );
+
+    if( (rc=build_pk_list( remusr, &pk_list, PUBKEY_USAGE_ENC )) )
+	goto leave;
+    compr_algo = select_algo_from_prefs( pk_list, PREFTYPE_COMPR );
+
+    /* prepare iobufs */
+    if( !(inp = iobuf_open(fname)) ) {
+	log_error("can't open %s: %s\n", fname? fname: "[stdin]",
+					strerror(errno) );
+	rc = G10ERR_OPEN_FILE;
+	goto leave;
+    }
+
+    if( (rc = open_outfile( fname, opt.armor? 1: 0, &out )))
+	goto leave;
+
+    /* prepare to calculate the MD over the input */
+    mfx.md = md_open( DIGEST_ALGO_SHA1, 0 );
+    iobuf_push_filter( inp, md_filter, &mfx );
+
+    if( opt.armor )
+	iobuf_push_filter( out, armor_filter, &afx );
+    efx.pk_list = pk_list;
+    /* fixme: set efx.cfx.datalen if known */
+    iobuf_push_filter( out, encrypt_filter, &efx );
+
+    if( opt.compress ) {
+	if( !compr_algo )
+	    ; /* don't use compression */
+	else {
+	    if( compr_algo == 1 )
+		zfx.algo = 1;
+	    iobuf_push_filter( out, compress_filter, &zfx );
+	}
+    }
+
+    /* build a one pass packet */
+    {
+	PKT_onepass_sig *ops;
+
+	ops = m_alloc_clear( sizeof *ops );
+	ops->sig_class = 0x00;
+	ops->digest_algo = DIGEST_ALGO_SHA1;
+	ops->pubkey_algo = 0;
+	ops->keyid[0] = 0;
+	ops->keyid[1] = 0;
+	ops->last = 1;
+
+	init_packet(&pkt);
+	pkt.pkttype = PKT_ONEPASS_SIG;
+	pkt.pkt.onepass_sig = ops;
+	rc = build_packet( out, &pkt );
+	free_packet( &pkt );
+	if( rc ) {
+	    log_error("build onepass_sig packet failed: %s\n",
+							g10_errstr(rc));
+	    goto leave;
+	}
+    }
+
+    /* setup the inner packet */
+    if( fname || opt.set_filename ) {
+	char *s = make_basename( opt.set_filename ? opt.set_filename : fname );
+	pt = m_alloc( sizeof *pt + strlen(s) - 1 );
+	pt->namelen = strlen(s);
+	memcpy(pt->name, s, pt->namelen );
+	m_free(s);
+    }
+    else { /* no filename */
+	pt = m_alloc( sizeof *pt - 1 );
+	pt->namelen = 0;
+    }
+    if( fname ) {
+	if( !(filesize = iobuf_get_filelength(inp)) )
+	    log_info(_("WARNING: `%s' is an empty file\n"), fname );
+
+	/* because the text_filter modifies the length of the
+	 * data, it is not possible to know the used length
+	 * without a double read of the file - to avoid that
+	 * we simple use partial length packets.
+	 */
+	if( opt.textmode )
+	    filesize = 0;
+    }
+    else
+	filesize = 0; /* stdin */
+    pt->timestamp = make_timestamp();
+    pt->mode = opt.textmode ? 't':'b';
+    pt->len = filesize;
+    pt->new_ctb = !pt->len;
+    pt->buf = inp;
+    pkt.pkttype = PKT_PLAINTEXT;
+    pkt.pkt.plaintext = pt;
+    /*cfx.datalen = filesize? calc_packet_length( &pkt ) : 0;*/
+    if( (rc = build_packet( out, &pkt )) )
+	log_error("build_packet(PLAINTEXT) failed: %s\n", g10_errstr(rc) );
+    pt->buf = NULL;
+
+    /* build the MDC faked signature packet */
+    {
+	PKT_signature *sig;
+	MD_HANDLE md;
+	byte buf[6];
+	size_t n;
+
+	sig = m_alloc_clear( sizeof *sig );
+	sig->version = 4;
+	sig->digest_algo = DIGEST_ALGO_SHA1;
+	md = md_copy( mfx.md );
+
+	md_putc( md, sig->version );
+	md_putc( md, sig->sig_class );
+	md_putc( md, sig->pubkey_algo );
+	md_putc( md, sig->digest_algo );
+	n = 6;
+	/* add some magic */
+	buf[0] = sig->version;
+	buf[1] = 0xff; buf[2] = 0; buf[3] = 0; buf[4] = 0; buf[5] = 6;
+	md_write( md, buf, 6 );
+	md_final( md );
+
+	/* pack the hash into data[0] */
+	memcpy( sig->digest_start, md_read( md, DIGEST_ALGO_SHA1), 2 );
+	sig->data[0] = mpi_alloc( (20+BYTES_PER_MPI_LIMB-1)
+				  /BYTES_PER_MPI_LIMB );
+	mpi_set_buffer( sig->data[0], md_read(md, DIGEST_ALGO_SHA1),
+				 md_digest_length(DIGEST_ALGO_SHA1), 0 );
+
+	md_close( md );
+
+	if( !rc ) { /* and write it */
+	    init_packet(&pkt);
+	    pkt.pkttype = PKT_SIGNATURE;
+	    pkt.pkt.signature = sig;
+	    rc = build_packet( out, &pkt );
+	    free_packet( &pkt );
+	    if( rc )
+		log_error("build MDC packet failed: %s\n", g10_errstr(rc) );
+	}
+	if( rc )
+	    goto leave;
+    }
+
+
+  leave:
+    if( rc )
+	iobuf_cancel(out);
+    else
+	iobuf_close(out);
+    iobuf_close(inp);
+    md_close( mfx.md );
+    release_pk_list( pk_list );
+    return rc;
+}
+
+
+
+
+
+
+
+
+
 /****************
  * Filter to do a complete public key encryption.
  */
diff --git a/g10/encr-data.c b/g10/encr-data.c
index c18a397bd..5061622da 100644
--- a/g10/encr-data.c
+++ b/g10/encr-data.c
@@ -45,7 +45,7 @@ typedef struct {
  * Decrypt the data, specified by ED with the key DEK.
  */
 int
-decrypt_data( PKT_encrypted *ed, DEK *dek )
+decrypt_data( void *procctx, PKT_encrypted *ed, DEK *dek )
 {
     decode_filter_ctx_t dfx;
     byte *p;
@@ -105,7 +105,7 @@ decrypt_data( PKT_encrypted *ed, DEK *dek )
 	return G10ERR_BAD_KEY;
     }
     iobuf_push_filter( ed->buf, decode_filter, &dfx );
-    proc_packets(ed->buf);
+    proc_packets( procctx, ed->buf);
     ed->buf = NULL;
     cipher_close(dfx.cipher_hd);
     return 0;
diff --git a/g10/free-packet.c b/g10/free-packet.c
index 78f81bd0a..e8a3a8af3 100644
--- a/g10/free-packet.c
+++ b/g10/free-packet.c
@@ -56,11 +56,9 @@ void
 free_seckey_enc( PKT_signature *sig )
 {
     int n, i;
-    n = pubkey_get_nsig( sig->pubkey_algo );
-    if( !n ) {
-	m_free(sig->data[0]);
-	sig->data[0] = NULL;
-    }
+    n = sig->pubkey_algo? pubkey_get_nsig( sig->pubkey_algo ) : 0;
+    if( !n )
+	mpi_free(sig->data[0]);
     for(i=0; i < n; i++ )
 	mpi_free( sig->data[i] );
     m_free(sig->hashed_data);
@@ -168,13 +166,11 @@ copy_signature( PKT_signature *d, PKT_signature *s )
     if( !d )
 	d = m_alloc(sizeof *d);
     memcpy( d, s, sizeof *d );
-    n = pubkey_get_nsig( s->pubkey_algo );
+    n = s->pubkey_algo? pubkey_get_nsig( s->pubkey_algo ) : 0;
     if( !n )
-	d->data[0] = cp_fake_data(s->data[0]);
-    else {
-	for(i=0; i < n; i++ )
-	    d->data[i] = mpi_copy( s->data[i] );
-    }
+	d->data[0] = mpi_copy(s->data[0]);
+    for(i=0; i < n; i++ )
+	d->data[i] = mpi_copy( s->data[i] );
     d->hashed_data = cp_data_block(s->hashed_data);
     d->unhashed_data = cp_data_block(s->unhashed_data);
     return d;
@@ -434,7 +430,7 @@ cmp_signatures( PKT_signature *a, PKT_signature *b )
     if( a->pubkey_algo != b->pubkey_algo )
 	return -1;
 
-    n = pubkey_get_nsig( a->pubkey_algo );
+    n = a->pubkey_algo? pubkey_get_nsig( a->pubkey_algo ) : 0;
     if( !n )
 	return -1; /* can't compare due to unknown algorithm */
     for(i=0; i < n; i++ ) {
diff --git a/g10/g10.c b/g10/g10.c
index 3ebcbe99f..ab6a28d2a 100644
--- a/g10/g10.c
+++ b/g10/g10.c
@@ -144,6 +144,7 @@ enum cmd_and_opt_values { aNull = 0,
     oComment,
     oThrowKeyid,
     oForceV3Sigs,
+    oForceMDC,
     oS2KMode,
     oS2KDigest,
     oS2KCipher,
@@ -220,6 +221,7 @@ static ARGPARSE_OPTS opts[] = {
     { oVerbose, "verbose",   0, N_("verbose") },
     { oQuiet,	"quiet",   0, N_("be somewhat more quiet") },
     { oForceV3Sigs, "force-v3-sigs", 0, N_("force v3 signatures") },
+    { oForceMDC, "force-mdc", 0, N_("always use a MDC for encryption") },
     { oDryRun, "dry-run",   0, N_("do not make any changes") },
     { oBatch, "batch",     0, N_("batch mode: never ask")},
     { oAnswerYes, "yes",       0, N_("assume yes on most questions")},
@@ -701,6 +703,7 @@ main( int argc, char **argv )
 	  case oComment: opt.comment_string = pargs.r.ret_str; break;
 	  case oThrowKeyid: opt.throw_keyid = 1; break;
 	  case oForceV3Sigs: opt.force_v3_sigs = 1; break;
+	  case oForceMDC: opt.force_mdc = 1; break;
 	  case oS2KMode:   opt.s2k_mode = pargs.r.ret_int; break;
 	  case oS2KDigest: s2k_digest_string = m_strdup(pargs.r.ret_str); break;
 	  case oS2KCipher: s2k_cipher_string = m_strdup(pargs.r.ret_str); break;
@@ -1240,7 +1243,7 @@ main( int argc, char **argv )
 		set_packet_list_mode(1);
 		opt.list_packets=1;
 	    }
-	    proc_packets( a );
+	    proc_packets(NULL, a );
 	    iobuf_close(a);
 	}
 	break;
diff --git a/g10/keyedit.c b/g10/keyedit.c
index 7ae006a68..1ba92a2cd 100644
--- a/g10/keyedit.c
+++ b/g10/keyedit.c
@@ -1,5 +1,5 @@
 /* keyedit.c - keyedit stuff
- *	Copyright (C) 1998 Free Software Foundation, Inc.
+ *	Copyright (C) 1998, 1999 Free Software Foundation, Inc.
  *
  * This file is part of GnuPG.
  *
@@ -56,6 +56,7 @@ static int count_uids_with_flag( KBNODE keyblock, unsigned flag );
 static int count_keys_with_flag( KBNODE keyblock, unsigned flag );
 static int count_selected_uids( KBNODE keyblock );
 static int count_selected_keys( KBNODE keyblock );
+static int menu_revsig( KBNODE keyblock );
 
 #define CONTROL_D ('D' - 'A' + 1)
 
@@ -67,6 +68,7 @@ static int count_selected_keys( KBNODE keyblock );
 
 #define NODFLG_SELUID (1<<8)  /* indicate the selected userid */
 #define NODFLG_SELKEY (1<<9)  /* indicate the selected key */
+#define NODFLG_SELSIG (1<<10) /* indicate a selected signature */
 
 
 struct sign_uid_attrib {
@@ -119,6 +121,8 @@ check_all_keysigs( KBNODE keyblock, int only_selected )
     int anyuid = 0;
 
     for( kbctx=NULL; (node=walk_kbnode( keyblock, &kbctx, 0)) ; ) {
+	int is_rev = 0;
+
 	if( node->pkt->pkttype == PKT_USER_ID ) {
 	    PKT_user_id *uid = node->pkt->pkt.user_id;
 
@@ -135,7 +139,8 @@ check_all_keysigs( KBNODE keyblock, int only_selected )
 	    }
 	}
 	else if( selected && node->pkt->pkttype == PKT_SIGNATURE
-		 && (node->pkt->pkt.signature->sig_class&~3) == 0x10 ) {
+		 && (node->pkt->pkt.signature->sig_class&~3) == 0x10
+		 && (is_rev = node->pkt->pkt.signature->sig_class == 0x30) ) {
 	    PKT_signature *sig = node->pkt->pkt.signature;
 	    int sigrc, selfsig;
 
@@ -161,14 +166,16 @@ check_all_keysigs( KBNODE keyblock, int only_selected )
 		break;
 	    }
 	    if( sigrc != '?' ) {
-		tty_printf("sig%c       %08lX %s   ",
+		tty_printf("%s%c       %08lX %s   ",
+			is_rev? "rev":"sig",
 			sigrc, sig->keyid[1], datestr_from_sig(sig));
 		if( sigrc == '%' )
 		    tty_printf("[%s] ", g10_errstr(rc) );
 		else if( sigrc == '?' )
 		    ;
 		else if( selfsig ) {
-		    tty_printf( _("[self-signature]") );
+		    tty_printf( is_rev? _("[revocation]")
+				      : _("[self-signature]") );
 		    if( sigrc == '!' )
 			has_selfsig = 1;
 		}
@@ -278,6 +285,8 @@ sign_uids( KBNODE keyblock, STRLIST locusr, int *ret_modified, int local )
 		&& (node->pkt->pkt.signature->sig_class&~3) == 0x10 ) {
 		if( sk_keyid[0] == node->pkt->pkt.signature->keyid[0]
 		    && sk_keyid[1] == node->pkt->pkt.signature->keyid[1] ) {
+		    /* Fixme: see whether there is a revocation in which
+		     * case we should allow to sign it again. */
 		    tty_printf(_("Already signed by key %08lX\n"),
 							(ulong)sk_keyid[1] );
 		    uidnode->flag &= ~NODFLG_MARK_A; /* remove mark */
@@ -514,7 +523,7 @@ keyedit_menu( const char *username, STRLIST locusr, STRLIST commands )
 {
     enum cmdids { cmdNONE = 0,
 	   cmdQUIT, cmdHELP, cmdFPR, cmdLIST, cmdSELUID, cmdCHECK, cmdSIGN,
-	   cmdLSIGN,
+	   cmdLSIGN, cmdREVSIG,
 	   cmdDEBUG, cmdSAVE, cmdADDUID, cmdDELUID, cmdADDKEY, cmdDELKEY,
 	   cmdTOGGLE, cmdSELKEY, cmdPASSWD, cmdTRUST, cmdPREF, cmdEXPIRE,
 	   cmdNOP };
@@ -550,6 +559,7 @@ keyedit_menu( const char *username, STRLIST locusr, STRLIST commands )
 	{ N_("pref")    , cmdPREF  , 0, N_("list preferences") },
 	{ N_("passwd")  , cmdPASSWD , 1, N_("change the passphrase") },
 	{ N_("trust")   , cmdTRUST , 0, N_("change the ownertrust") },
+	{ N_("revsig")  , cmdREVSIG , 0, N_("revoke signatures") },
 
     { NULL, cmdNONE } };
     enum cmdids cmd;
@@ -852,6 +862,13 @@ keyedit_menu( const char *username, STRLIST locusr, STRLIST commands )
 	  case cmdNOP:
 	    break;
 
+	  case cmdREVSIG:
+	    if( menu_revsig( keyblock ) ) {
+		redisplay = 1;
+		modified = 1;
+	    }
+	    break;
+
 	  default:
 	    tty_printf("\n");
 	    tty_printf(_("Invalid command  (try \"help\")\n"));
@@ -1490,3 +1507,160 @@ count_selected_keys( KBNODE keyblock )
     return count_keys_with_flag( keyblock, NODFLG_SELKEY);
 }
 
+/*
+ * Ask whether the signature should be revoked.  If the user commits this,
+ * flag bit MARK_A is set on the signature and the user ID.
+ */
+static void
+ask_revoke_sig( KBNODE keyblock, KBNODE node )
+{
+    PKT_signature *sig = node->pkt->pkt.signature;
+    KBNODE unode = find_prev_kbnode( keyblock, node, PKT_USER_ID );
+
+    if( !unode ) {
+	log_error("Oops: no user ID for signature\n");
+	return;
+    }
+
+    tty_printf(_("user ID: \""));
+    tty_print_string( unode->pkt->pkt.user_id->name,
+		      unode->pkt->pkt.user_id->len );
+    tty_printf(_("\"\nsigned with your key %08lX at %s\n"),
+		sig->keyid[1], datestr_from_sig(sig) );
+
+    if( cpr_get_answer_is_yes("ask_revoke_sig.one",
+	 _("Create a revocation certificate for this signature? (y/N)")) ) {
+	node->flag |= NODFLG_MARK_A;
+	unode->flag |= NODFLG_MARK_A;
+    }
+}
+
+/****************
+ * Display all user ids of the current public key together with signatures
+ * done by one of our keys.  Then walk over all this sigs and ask the user
+ * whether he wants to revoke this signature.
+ * Return: True when the keyblock has changed.
+ */
+static int
+menu_revsig( KBNODE keyblock )
+{
+    PKT_signature *sig;
+    PKT_public_key *primary_pk;
+    KBNODE node;
+    int changed = 0;
+    int upd_trust = 0;
+    int rc, any;
+
+    /* FIXME: detect duplicates here  */
+    tty_printf("You have signed these user IDs:\n");
+    for( node = keyblock; node; node = node->next ) {
+	node->flag &= ~(NODFLG_SELSIG | NODFLG_MARK_A);
+	if( node->pkt->pkttype == PKT_USER_ID ) {
+	    PKT_user_id *uid = node->pkt->pkt.user_id;
+	    /* Hmmm: Should we show only UIDs with a signature? */
+	    tty_printf("     ");
+	    tty_print_string( uid->name, uid->len );
+	    tty_printf("\n");
+	}
+	else if( node->pkt->pkttype == PKT_SIGNATURE
+		&& ((sig = node->pkt->pkt.signature),
+		     !seckey_available( sig->keyid )  ) ) {
+	    if( (sig->sig_class&~3) == 0x10 ) {
+		tty_printf("   signed by %08lX at %s\n",
+			    sig->keyid[1], datestr_from_sig(sig) );
+		node->flag |= NODFLG_SELSIG;
+	    }
+	    else if( sig->sig_class == 0x30 ) {
+		tty_printf("   revoked by %08lX at %s\n",
+			    sig->keyid[1], datestr_from_sig(sig) );
+	    }
+	}
+    }
+
+    /* ask */
+    for( node = keyblock; node; node = node->next ) {
+	if( !(node->flag & NODFLG_SELSIG) )
+	    continue;
+	ask_revoke_sig( keyblock, node );
+    }
+
+    /* present selected */
+    any = 0;
+    for( node = keyblock; node; node = node->next ) {
+	if( !(node->flag & NODFLG_MARK_A) )
+	    continue;
+	if( !any ) {
+	    any = 1;
+	    tty_printf("You are about to revoke these signatures:\n");
+	}
+	if( node->pkt->pkttype == PKT_USER_ID ) {
+	    PKT_user_id *uid = node->pkt->pkt.user_id;
+	    tty_printf("     ");
+	    tty_print_string( uid->name, uid->len );
+	    tty_printf("\n");
+	}
+	else if( node->pkt->pkttype == PKT_SIGNATURE ) {
+	    sig = node->pkt->pkt.signature;
+	    tty_printf("   signed by %08lX at %s\n",
+			    sig->keyid[1], datestr_from_sig(sig) );
+	}
+    }
+    if( !any )
+	return 0; /* none selected */
+
+    if( !cpr_get_answer_is_yes("ask_revoke_sig.okay",
+	 _("Really create the revocation certificates? (y/N)")) )
+	return 0; /* forget it */
+
+
+    /* now we can sign the user ids */
+  reloop: /* (must use this, because we are modifing the list) */
+    primary_pk = keyblock->pkt->pkt.public_key;
+    for( node=keyblock; node; node = node->next ) {
+	KBNODE unode;
+	PACKET *pkt;
+	struct sign_uid_attrib attrib;
+	PKT_secret_key *sk;
+
+	if( !(node->flag & NODFLG_MARK_A)
+	    || node->pkt->pkttype != PKT_SIGNATURE )
+	    continue;
+	unode = find_prev_kbnode( keyblock, node, PKT_USER_ID );
+	assert( unode ); /* we already checked this */
+
+	memset( &attrib, 0, sizeof attrib );
+	node->flag &= ~NODFLG_MARK_A;
+	sk = m_alloc_secure_clear( sizeof *sk );
+	if( get_seckey( sk, node->pkt->pkt.signature->keyid ) ) {
+	    log_info(_("no secret key\n"));
+	    continue;
+	}
+	rc = make_keysig_packet( &sig, primary_pk,
+				       unode->pkt->pkt.user_id,
+				       NULL,
+				       sk,
+				       0x30, 0,
+				       sign_uid_mk_attrib,
+				       &attrib );
+	free_secret_key(sk);
+	if( rc ) {
+	    log_error(_("signing failed: %s\n"), g10_errstr(rc));
+	    return changed;
+	}
+	changed = 1; /* we changed the keyblock */
+	upd_trust = 1;
+
+	pkt = m_alloc_clear( sizeof *pkt );
+	pkt->pkttype = PKT_SIGNATURE;
+	pkt->pkt.signature = sig;
+	insert_kbnode( unode, new_kbnode(pkt), PKT_SIGNATURE );
+	goto reloop;
+    }
+
+    if( upd_trust )
+	clear_trust_checked_flag( primary_pk );
+
+    return changed;
+}
+
+
diff --git a/g10/mainproc.c b/g10/mainproc.c
index 5d33f4edc..528f520ac 100644
--- a/g10/mainproc.c
+++ b/g10/mainproc.c
@@ -1,5 +1,5 @@
 /* mainproc.c - handle packets
- *	Copyright (C) 1998 Free Software Foundation, Inc.
+ *	Copyright (C) 1998, 1999 Free Software Foundation, Inc.
  *
  * This file is part of GnuPG.
  *
@@ -42,8 +42,9 @@
 /****************
  * Structure to hold the context
  */
-
-typedef struct {
+typedef struct mainproc_context *CTX;
+struct mainproc_context {
+    struct mainproc_context *anchor;
     PKT_public_key *last_pubkey;
     PKT_secret_key *last_seckey;
     PKT_user_id     *last_user_id;
@@ -59,7 +60,8 @@ typedef struct {
     IOBUF iobuf;    /* used to get the filename etc. */
     int trustletter; /* temp usage in list_node */
     ulong local_id;    /* ditto */
-} *CTX;
+    int is_encrypted;  /* used to check the MDC */
+};
 
 
 static int do_proc_packets( CTX c, IOBUF a );
@@ -226,7 +228,8 @@ proc_encrypted( CTX c, PACKET *pkt )
 {
     int result = 0;
 
-    /*printf("dat: %sencrypted data\n", c->dek?"":"conventional ");*/
+    /*log_debug("dat: %sencrypted data\n", c->dek?"":"conventional ");*/
+    c->is_encrypted = 1;
     if( !c->dek && !c->last_was_session_key ) {
 	/* assume this is old conventional encrypted data */
 	c->dek = passphrase_to_dek( NULL,
@@ -236,7 +239,7 @@ proc_encrypted( CTX c, PACKET *pkt )
     else if( !c->dek )
 	result = G10ERR_NO_SECKEY;
     if( !result )
-	result = decrypt_data( pkt->pkt.encrypted, c->dek );
+	result = decrypt_data( c, pkt->pkt.encrypted, c->dek );
     m_free(c->dek); c->dek = NULL;
     if( result == -1 )
 	;
@@ -289,10 +292,13 @@ proc_plaintext( CTX c, PACKET *pkt )
 	     * to do it. (We could use a special packet type to indicate
 	     * this, but this may also be faked - it simply can't be verified
 	     * and is _no_ security issue)
+	     * Hmmm: There is one problem: The MDC also uses a keyid of 0
+	     * and a pubkey algo of 0 - the only difference is that the
+	     * sig_class will be 0.
 	     */
 	    if( n->pkt->pkt.onepass_sig->sig_class == 0x01
 		&& !n->pkt->pkt.onepass_sig->keyid[0]
-		&& !n->pkt->pkt.onepass_sig->keyid[1]  )
+		&& !n->pkt->pkt.onepass_sig->keyid[1] )
 		clearsig = 1;
 	}
     }
@@ -321,14 +327,14 @@ proc_plaintext( CTX c, PACKET *pkt )
 static int
 proc_compressed_cb( IOBUF a, void *info )
 {
-    return proc_signature_packets( a, ((CTX)info)->signed_data,
-				      ((CTX)info)->sigfilename );
+    return proc_signature_packets( info, a, ((CTX)info)->signed_data,
+					    ((CTX)info)->sigfilename );
 }
 
 static int
 proc_encrypt_cb( IOBUF a, void *info )
 {
-    return proc_encryption_packets( a );
+    return proc_encryption_packets( info, a );
 }
 
 static void
@@ -339,19 +345,26 @@ proc_compressed( CTX c, PACKET *pkt )
 
     /*printf("zip: compressed data packet\n");*/
     if( c->sigs_only )
-	rc = handle_compressed( zd, proc_compressed_cb, c );
+	rc = handle_compressed( c, zd, proc_compressed_cb, c );
     else if( c->encrypt_only )
-	rc = handle_compressed( zd, proc_encrypt_cb, c );
+	rc = handle_compressed( c, zd, proc_encrypt_cb, c );
     else
-	rc = handle_compressed( zd, NULL, NULL );
+	rc = handle_compressed( c, zd, NULL, NULL );
     if( rc )
 	log_error("uncompressing failed: %s\n", g10_errstr(rc));
     free_packet(pkt);
     c->last_was_session_key = 0;
 }
 
-
-
+static int
+is_encrypted( CTX c )
+{
+    for( ; c; c = c->anchor ) {
+	if( c->is_encrypted )
+	    return 1;
+    }
+    return 0;
+}
 
 /****************
  * check the signature
@@ -370,17 +383,9 @@ do_check_sig( CTX c, KBNODE node, int *is_selfsig )
     sig = node->pkt->pkt.signature;
 
     algo = sig->digest_algo;
-    if( !algo )
-	return G10ERR_PUBKEY_ALGO;
     if( (rc=check_digest_algo(algo)) )
 	return rc;
 
-    if( c->mfx.md ) {
-	m_check(c->mfx.md);
-	if( c->mfx.md->list )
-	    m_check( c->mfx.md->list );
-    }
-
     if( sig->sig_class == 0x00 ) {
 	if( c->mfx.md )
 	    md = md_copy( c->mfx.md );
@@ -411,7 +416,12 @@ do_check_sig( CTX c, KBNODE node, int *is_selfsig )
     }
     else
 	return G10ERR_SIG_CLASS;
-    rc = signature_check( sig, md );
+    if( sig->pubkey_algo )
+	rc = signature_check( sig, md );
+    else if( !is_encrypted( c ) )
+	rc = G10ERR_NOT_ENCRYPTED;
+    else
+	rc = mdc_kludge_check( sig, md );
     md_close(md);
 
     return rc;
@@ -697,19 +707,25 @@ list_node( CTX c, KBNODE node )
 
 
 int
-proc_packets( IOBUF a )
+proc_packets( void *anchor, IOBUF a )
 {
+    int rc;
     CTX c = m_alloc_clear( sizeof *c );
-    int rc = do_proc_packets( c, a );
+
+    c->anchor = anchor;
+    rc = do_proc_packets( c, a );
     m_free( c );
     return rc;
 }
 
 int
-proc_signature_packets( IOBUF a, STRLIST signedfiles, const char *sigfilename )
+proc_signature_packets( void *anchor, IOBUF a,
+			STRLIST signedfiles, const char *sigfilename )
 {
     CTX c = m_alloc_clear( sizeof *c );
     int rc;
+
+    c->anchor = anchor;
     c->sigs_only = 1;
     c->signed_data = signedfiles;
     c->sigfilename = sigfilename;
@@ -719,10 +735,12 @@ proc_signature_packets( IOBUF a, STRLIST signedfiles, const char *sigfilename )
 }
 
 int
-proc_encryption_packets( IOBUF a )
+proc_encryption_packets( void *anchor, IOBUF a )
 {
     CTX c = m_alloc_clear( sizeof *c );
     int rc;
+
+    c->anchor = anchor;
     c->encrypt_only = 1;
     rc = do_proc_packets( c, a );
     m_free( c );
@@ -845,23 +863,41 @@ check_sig_and_print( CTX c, KBNODE node )
     PKT_signature *sig = node->pkt->pkt.signature;
     const char *astr, *tstr;
     int rc;
+    int mdc_hack = !sig->pubkey_algo;
 
-    if( opt.skip_verify ) {
+    if( opt.skip_verify && !mdc_hack ) {
 	log_info(_("signature verification suppressed\n"));
 	return 0;
     }
 
-    tstr = asctimestamp(sig->timestamp);
-    astr = pubkey_algo_to_string( sig->pubkey_algo );
-    log_info(_("Signature made %.*s using %s key ID %08lX\n"),
+    if( !mdc_hack ) {
+	tstr = asctimestamp(sig->timestamp);
+	astr = pubkey_algo_to_string( sig->pubkey_algo );
+	log_info(_("Signature made %.*s using %s key ID %08lX\n"),
 	    (int)strlen(tstr), tstr, astr? astr: "?", (ulong)sig->keyid[1] );
+    }
 
     rc = do_check_sig(c, node, NULL );
     if( rc == G10ERR_NO_PUBKEY && opt.keyserver_name ) {
 	if( !hkp_ask_import( sig->keyid ) )
 	    rc = do_check_sig(c, node, NULL );
     }
-    if( !rc || rc == G10ERR_BAD_SIGN ) {
+    if( mdc_hack ) {
+	if( !rc ) {
+	    if( opt.verbose )
+		log_info(_("encrypted message is valid\n"));
+	    write_status( STATUS_GOODMDC );
+	}
+	else if( rc == G10ERR_BAD_SIGN ) {
+	    log_error(_("WARNING: encrypted message has been manipulated!\n"));
+	    write_status( STATUS_BADMDC );
+	}
+	else {
+	    write_status( STATUS_ERRMDC );
+	    log_error(_("Can't check MDC: %s\n"), g10_errstr(rc) );
+	}
+    }
+    else if( !rc || rc == G10ERR_BAD_SIGN ) {
 	KBNODE un, keyblock;
 	char *us;
 	int count=0;
diff --git a/g10/options.h b/g10/options.h
index c01bbd2a6..4f5457a4a 100644
--- a/g10/options.h
+++ b/g10/options.h
@@ -44,6 +44,7 @@ struct {
     int list_packets; /* list-packets mode */
     int def_cipher_algo;
     int force_v3_sigs;
+    int force_mdc;
     int def_digest_algo;
     int def_compress_algo;
     const char *def_secret_key;
diff --git a/g10/packet.h b/g10/packet.h
index 36115be5b..312668317 100644
--- a/g10/packet.h
+++ b/g10/packet.h
@@ -233,9 +233,10 @@ typedef enum {
 
 
 /*-- mainproc.c --*/
-int proc_packets( IOBUF a );
-int proc_signature_packets( IOBUF a, STRLIST signedfiles, const char *sigfile );
-int proc_encryption_packets( IOBUF a );
+int proc_packets( void *ctx, IOBUF a );
+int proc_signature_packets( void *ctx, IOBUF a,
+			    STRLIST signedfiles, const char *sigfile );
+int proc_encryption_packets( void *ctx, IOBUF a );
 int list_packets( IOBUF a );
 
 /*-- parse-packet.c --*/
@@ -301,6 +302,7 @@ int cmp_user_ids( PKT_user_id *a, PKT_user_id *b );
 
 /*-- sig-check.c --*/
 int signature_check( PKT_signature *sig, MD_HANDLE digest );
+int mdc_kludge_check( PKT_signature *sig, MD_HANDLE digest );
 
 /*-- seckey-cert.c --*/
 int is_secret_key_protected( PKT_secret_key *sk );
@@ -311,11 +313,11 @@ int protect_secret_key( PKT_secret_key *sk, DEK *dek );
 int get_session_key( PKT_pubkey_enc *k, DEK *dek );
 
 /*-- compress.c --*/
-int handle_compressed( PKT_compressed *cd,
+int handle_compressed( void *ctx, PKT_compressed *cd,
 		       int (*callback)(IOBUF, void *), void *passthru );
 
 /*-- encr-data.c --*/
-int decrypt_data( PKT_encrypted *ed, DEK *dek );
+int decrypt_data( void *ctx, PKT_encrypted *ed, DEK *dek );
 int encrypt_data( PKT_encrypted *ed, DEK *dek );
 
 /*-- plaintext.c --*/
diff --git a/g10/parse-packet.c b/g10/parse-packet.c
index 61a226a39..94bf0f38d 100644
--- a/g10/parse-packet.c
+++ b/g10/parse-packet.c
@@ -1024,7 +1024,7 @@ parse_signature( IOBUF inp, int pkttype, unsigned long pktlen,
     sig->digest_start[0] = iobuf_get_noeof(inp); pktlen--;
     sig->digest_start[1] = iobuf_get_noeof(inp); pktlen--;
 
-    if( is_v4 ) { /*extract required information */
+    if( is_v4 && sig->pubkey_algo ) { /*extract required information */
 	const byte *p;
 
 	/* set sig->flags.unknown_critical if there is a
@@ -1065,24 +1065,36 @@ parse_signature( IOBUF inp, int pkttype, unsigned long pktlen,
 	}
     }
 
-    ndata = pubkey_get_nsig(sig->pubkey_algo);
-    if( !ndata ) {
-	if( list_mode )
-	    printf("\tunknown algorithm %d\n", sig->pubkey_algo );
-	unknown_pubkey_warning( sig->pubkey_algo );
-	/* we store the plain material in data[0], so that we are able
-	 * to write it back with build_packet() */
-	sig->data[0] = read_rest(inp, &pktlen );
+    if( !sig->pubkey_algo ) {
+	n = pktlen;
+	sig->data[0] = mpi_read(inp, &n, 0 );
+	pktlen -=n;
+	if( list_mode ) {
+	    printf("\tMDC data: ");
+	    mpi_print(stdout, sig->data[0], mpi_print_mode );
+	    putchar('\n');
+	}
     }
     else {
-	for( i=0; i < ndata; i++ ) {
-	    n = pktlen;
-	    sig->data[i] = mpi_read(inp, &n, 0 );
-	    pktlen -=n;
-	    if( list_mode ) {
-		printf("\tdata: ");
-		mpi_print(stdout, sig->data[i], mpi_print_mode );
-		putchar('\n');
+	ndata = pubkey_get_nsig(sig->pubkey_algo);
+	if( !ndata ) {
+	    if( list_mode )
+		printf("\tunknown algorithm %d\n", sig->pubkey_algo );
+	    unknown_pubkey_warning( sig->pubkey_algo );
+	    /* we store the plain material in data[0], so that we are able
+	     * to write it back with build_packet() */
+	    sig->data[0] = read_rest(inp, &pktlen );
+	}
+	else {
+	    for( i=0; i < ndata; i++ ) {
+		n = pktlen;
+		sig->data[i] = mpi_read(inp, &n, 0 );
+		pktlen -=n;
+		if( list_mode ) {
+		    printf("\tdata: ");
+		    mpi_print(stdout, sig->data[i], mpi_print_mode );
+		    putchar('\n');
+		}
 	    }
 	}
     }
diff --git a/g10/revoke.c b/g10/revoke.c
index 6467b8482..d93c7a462 100644
--- a/g10/revoke.c
+++ b/g10/revoke.c
@@ -201,4 +201,190 @@ gen_revoke( const char *uname )
     return rc;
 }
 
+#if 0 /* The code is not complete but anyway, now we use */
+      /* the edit menu to revoke signature */
+/****************
+ * Return true if there is already a revocation signature for KEYID
+ * in KEYBLOCK at point node.
+ */
+static int
+already_revoked( const KBNODE keyblock, const KBNODE node, u32 *keyid ) 							 ) {
+{
+    const KBNODE n = find_prev_kbnode( keyblock, node, PKT_USER_ID );
+
+    for( ; n; n = n->next ) {
+	PKT_signature *sig;
+	if( n->pkt->pkttype == PKT_SIGNATURE
+	    && (sig = node->pkt->pkt.signature)->sig_class == 0x30
+	    && sig->keyid[0] == keyid[0]
+	    && sig->keyid[1] == keyid[1] )
+	    return 1;
+	}
+	else if( n->pkt->pkttype == PKT_USER_ID
+	    break;
+	else if( n->pkt->pkttype == PKT_PUBLIC_SUBKEY
+	    break;
+    }
+    return 0;
+}
+
+/****************
+ * Ask whether the signature should be revoked.  If the user commits this,
+ * flag bit 0 is set.
+ */
+static void
+ask_revoke_sig( KBNODE keyblock, KBNODE node, PKT_signature *sig )							    ) {
+{
+    KBNODE unode = find_prev_kbnode( keyblock, node, PKT_USER_ID );
+
+    if( !unode ) {
+	log_error("Oops: no user ID for signature\n");
+	return;
+    }
+
+    tty_printf(_("user ID: \""));
+    tty_print_string( unode->pkt->pkt.user_id->name,
+		      unode->pkt->pkt.user_id->len, 0 );
+    tty_printf(_("\"\nsigned with your key %08lX at %s\n"),
+		sig->keyid[1], datestr_from_sig(sig) );
+
+    if( cpr_get_answer_is_yes("ask_revoke_sig.one",
+	 _("Create a revocation certificate for this signature? (y/N)")) ) {
+	node->flag |= 1;
+    }
+}
+
+/****************
+ * Generate a signature revocation certificate for UNAME
+ */
+int
+gen_sig_revoke( const char *uname )
+{
+    int rc = 0;
+    armor_filter_context_t afx;
+    compress_filter_context_t zfx;
+    PACKET pkt;
+    IOBUF out = NULL;
+    KBNODE keyblock = NULL;
+    KBNODE node;
+    KBPOS kbpos;
+    int uidchg;
+
+    if( opt.batch ) {
+	log_error(_("sorry, can't do this in batch mode\n"));
+	return G10ERR_GENERAL;
+    }
+
+
+    memset( &afx, 0, sizeof afx);
+    memset( &zfx, 0, sizeof zfx);
+    init_packet( &pkt );
+
+
+    /* get the keyblock */
+    rc = find_keyblock_byname( &kbpos, uname );
+    if( rc ) {
+	log_error(_("public key for user `%s' not found\n"), uname );
+	goto leave;
+    }
+
+    /* read the keyblock */
+    rc = read_keyblock( &kbpos, &keyblock );
+    if( rc ) {
+	log_error(_("error reading the certificate: %s\n"), g10_errstr(rc) );
+	goto leave;
+    }
+
+    /* get the keyid from the keyblock */
+    node = find_kbnode( keyblock, PKT_PUBLIC_KEY );
+    if( !node ) {
+	log_error(_("Oops; public key lost!\n"));
+	rc = G10ERR_GENERAL;
+	goto leave;
+    }
+
+    if( (rc = open_outfile( NULL, 0, &out )) )
+	goto leave;
+
+    if( opt.armor ) {
+       afx.what = 1;
+       iobuf_push_filter( out, armor_filter, &afx );
+    }
+
+    /* Now walk over all signatures which we did with one of
+     * our secret keys.  Hmmm: Should we check for duplicate signatures */
+    clear_kbnode_flags( flags );
+    for( node = keyblock; node; node = node->next ) {
+	PKT_signature *sig;
+	if( node->pkt->pkttype == PKT_SIGNATURE
+	    && ((sig = node->pkt->pkt.signature)->sig_class&~3) == 0x10
+	    && seckey_available( sig->keyid )
+	    && !already_revoked( keyblock, node, sig->keyid ) ) {							     ) {
+	    ask_revoke_sig( keyblock, node, sig )
+	}
+	else if( node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+	    break;
+    }
+
+
+    for( node = keyblock; node; node = node->next ) { {
+	if( (node->flag & 1) )
+	    break;
+    }
+    if( !node ) {
+	log_info(_("nothing to revoke\n"));
+	iobuf_cancel(out);
+	out = NULL;
+	goto leave;
+    }
+
+    init_packet( &pkt );
+    pkt.pkttype = PKT_PUBLIC_KEY;
+    pkt.pkt.public_key = keyblock->pkt->pkt.public_key;
+    rc = build_packet( out, &pkt );
+    if( rc ) {
+	log_error(_("build_packet failed: %s\n"), g10_errstr(rc) );
+	goto leave;
+    }
+    uidchg = 1;
+    for( node = keyblock; node; node = node->next ) {
+	if( node->pkt->pkttype == PKT_USER_ID )
+	    uidchg = 1;
+	if( !(node->flag & 1) )
+	    continue;
+
+	if( uidchg ) {
+	    /* create a user ID packet */
+	    .......
+	    uidchg = 0;
+	}
+
+	/* create it */
+	rc = make_keysig_packet( &sig, pk, NULL, NULL, sk, 0x30, 0, NULL, NULL);
+	if( rc ) {
+	    log_error(_("make_keysig_packet failed: %s\n"), g10_errstr(rc));
+	    goto leave;
+	}
+	init_packet( &pkt );
+	pkt.pkttype = PKT_SIGNATURE;
+	pkt.pkt.signature = sig;
+
+	rc = build_packet( out, &pkt );
+	if( rc ) {
+	    log_error(_("build_packet failed: %s\n"), g10_errstr(rc) );
+	    goto leave;
+	}
+    }
+
+  leave:
+    release_kbnode( keyblock );
+    if( !out )
+	;
+    else if( rc )
+	iobuf_cancel(out);
+    else
+	iobuf_close(out);
+    return rc;
+}
+#endif /* unused code */
 
diff --git a/g10/sig-check.c b/g10/sig-check.c
index 885a5b587..8b1f51c3d 100644
--- a/g10/sig-check.c
+++ b/g10/sig-check.c
@@ -45,7 +45,7 @@ static int do_check( PKT_public_key *pk, PKT_signature *sig,
 
 /****************
  * Check the signature which is contained in SIG.
- * The md5handle should be currently open, so that this function
+ * The MD_HANDLE should be currently open, so that this function
  * is able to append some data, before finalizing the digest.
  */
 int
@@ -54,7 +54,6 @@ signature_check( PKT_signature *sig, MD_HANDLE digest )
     PKT_public_key *pk = m_alloc_clear( sizeof *pk );
     int rc=0;
 
-
     if( is_RSA(sig->pubkey_algo) )
 	write_status(STATUS_RSA_OR_IDEA);
 
@@ -108,6 +107,94 @@ signature_check( PKT_signature *sig, MD_HANDLE digest )
 }
 
 
+
+/****************
+ * Check the MDC which is contained in SIG.
+ * The MD_HANDLE should be currently open, so that this function
+ * is able to append some data, before finalizing the digest.
+ */
+int
+mdc_kludge_check( PKT_signature *sig, MD_HANDLE digest )
+{
+    int rc=0;
+
+    if( (rc=check_digest_algo(sig->digest_algo)) )
+	return rc;
+
+    /* make sure the digest algo is enabled (in case of a detached mdc??) */
+    md_enable( digest, sig->digest_algo );
+
+    /* complete the digest */
+    if( sig->version >= 4 )
+	md_putc( digest, sig->version );
+    md_putc( digest, sig->sig_class );
+    if( sig->version < 4 ) {
+	u32 a = sig->timestamp;
+	md_putc( digest, (a >> 24) & 0xff );
+	md_putc( digest, (a >> 16) & 0xff );
+	md_putc( digest, (a >>	8) & 0xff );
+	md_putc( digest,  a	   & 0xff );
+    }
+    else {
+	byte buf[6];
+	size_t n;
+	md_putc( digest, sig->pubkey_algo );
+	md_putc( digest, sig->digest_algo );
+	if( sig->hashed_data ) {
+	    n = (sig->hashed_data[0] << 8) | sig->hashed_data[1];
+	    md_write( digest, sig->hashed_data, n+2 );
+	    n += 6;
+	}
+	else
+	    n = 6;
+	/* add some magic */
+	buf[0] = sig->version;
+	buf[1] = 0xff;
+	buf[2] = n >> 24;
+	buf[3] = n >> 16;
+	buf[4] = n >>  8;
+	buf[5] = n;
+	md_write( digest, buf, 6 );
+    }
+    md_final( digest );
+
+    rc = G10ERR_BAD_SIGN;
+    {	const byte *s1 = md_read( digest, sig->digest_algo );
+	int s1len = md_digest_length( sig->digest_algo );
+
+	log_hexdump( "MDC calculated", s1, s1len );
+
+	if( !sig->data[0] )
+	    log_debug("sig_data[0] is NULL\n");
+	else {
+	    unsigned s2len;
+	    byte *s2;
+	    s2 = mpi_get_buffer( sig->data[0], &s2len, NULL );
+	    log_hexdump( "MDC stored    ", s2, s2len );
+
+	    if( s2len != s1len )
+		log_debug("MDC check: len differ: %d/%d\n", s1len, s2len);
+	    else if( memcmp( s1, s2, s1len ) )
+		log_debug("MDC check: hashs differ\n");
+	    else
+		rc = 0;
+	    m_free(s2);
+	}
+    }
+
+    if( !rc && sig->flags.unknown_critical ) {
+	log_info(_("assuming bad MDC due to an unknown critical bit\n"));
+	rc = G10ERR_BAD_SIGN;
+    }
+    sig->flags.checked = 1;
+    sig->flags.valid = !rc;
+
+    /* FIXME: check that we are actually in an encrypted packet */
+
+    return rc;
+}
+
+
 /****************
  * This function gets called by pubkey_verify() if the algorithm needs it.
  */
diff --git a/g10/sign.c b/g10/sign.c
index 8924adab8..8cf5be7f5 100644
--- a/g10/sign.c
+++ b/g10/sign.c
@@ -656,7 +656,7 @@ make_keysig_packet( PKT_signature **ret_sig, PKT_public_key *pk,
     MD_HANDLE md;
 
     assert( (sigclass >= 0x10 && sigclass <= 0x13)
-	    || sigclass == 0x20 || sigclass == 0x18 );
+	    || sigclass == 0x20 || sigclass == 0x18 || sigclass == 0x30 );
     if( !digest_algo ) {
 	switch( sk->pubkey_algo ) {
 	  case PUBKEY_ALGO_DSA: digest_algo = DIGEST_ALGO_SHA1; break;
diff --git a/g10/status.c b/g10/status.c
index 9af3c9a5f..a832ea713 100644
--- a/g10/status.c
+++ b/g10/status.c
@@ -109,6 +109,9 @@ write_status_text ( int no, const char *text)
       case STATUS_DECRYPTION_OKAY: s = "DECRYPTION_OKAY\n"; break;
       case STATUS_MISSING_PASSPHRASE: s = "MISSING_PASSPHRASE\n"; break;
       case STATUS_GOOD_PASSPHRASE : s = "GOOD_PASSPHRASE\n"; break;
+      case STATUS_GOODMDC	 : s = "GOODMDC\n"; break;
+      case STATUS_BADMDC	 : s = "BADMDC\n"; break;
+      case STATUS_ERRMDC	 : s = "ERRMDC\n"; break;
       default: s = "?\n"; break;
     }
 
diff --git a/g10/status.h b/g10/status.h
index 083d7ce41..d8e13b70e 100644
--- a/g10/status.h
+++ b/g10/status.h
@@ -60,6 +60,9 @@
 #define STATUS_DECRYPTION_OKAY	 30
 #define STATUS_MISSING_PASSPHRASE 31
 #define STATUS_GOOD_PASSPHRASE	32
+#define STATUS_GOODMDC		33
+#define STATUS_BADMDC		34
+#define STATUS_ERRMDC		35
 
 /*-- status.c --*/
 void set_status_fd ( int fd );
diff --git a/g10/verify.c b/g10/verify.c
index 4c8ea0196..589b1b7bb 100644
--- a/g10/verify.c
+++ b/g10/verify.c
@@ -77,7 +77,7 @@ verify_signatures( int nfiles, char **files )
     sl = NULL;
     for(i=1 ; i < nfiles; i++ )
 	add_to_strlist( &sl, files[i] );
-    rc = proc_signature_packets( fp, sl, sigfile );
+    rc = proc_signature_packets( NULL, fp, sl, sigfile );
     free_strlist(sl);
     iobuf_close(fp);
     return rc;
diff --git a/include/errors.h b/include/errors.h
index 32d1ea55e..247951271 100644
--- a/include/errors.h
+++ b/include/errors.h
@@ -70,7 +70,7 @@
 #define G10ERR_NETWORK	      48  /* general network error */
 #define G10ERR_UNKNOWN_HOST   49
 #define G10ERR_SELFTEST_FAILED 50
-
+#define G10ERR_NOT_ENCRYPTED  51
 
 #ifndef HAVE_STRERROR
 char *strerror( int n );
diff --git a/mpi/ChangeLog b/mpi/ChangeLog
index 95f0e4055..7d66b809b 100644
--- a/mpi/ChangeLog
+++ b/mpi/ChangeLog
@@ -1,3 +1,9 @@
+Mon Apr 26 17:48:15 CEST 1999  Werner Koch  <wk@isil.d.shuttle.de>
+
+	* mpih-add.c, mpih-sub.c: Removed
+	* mpi-inline.c: New.
+	* mpi-inline.h: Make it usable by mpi-inline.c.
+
 Sun Apr 18 10:11:28 CEST 1999  Werner Koch  <wk@isil.d.shuttle.de>
 
 	* mpih-mul.c (mpihelp_mul_n): Fixed use of memory region.
diff --git a/mpi/Makefile.am b/mpi/Makefile.am
index 2f743093e..42acb55fe 100644
--- a/mpi/Makefile.am
+++ b/mpi/Makefile.am
@@ -22,6 +22,7 @@ libmpi_a_SOURCES = longlong.h	  \
 	      mpi-gcd.c      \
 	      mpi-internal.h \
 	      mpi-inline.h   \
+	      mpi-inline.c   \
 	      mpi-inv.c      \
 	      mpi-mul.c      \
 	      mpi-pow.c      \
@@ -29,8 +30,6 @@ libmpi_a_SOURCES = longlong.h	  \
 	      mpi-scan.c     \
 	      mpicoder.c     \
 	      mpih-cmp.c     \
-	      mpih-add.c     \
-	      mpih-sub.c     \
 	      mpih-div.c     \
 	      mpih-mul.c     \
 	      mpiutil.c      \
diff --git a/mpi/mpi-inline.c b/mpi/mpi-inline.c
new file mode 100644
index 000000000..7a2e7a4fd
--- /dev/null
+++ b/mpi/mpi-inline.c
@@ -0,0 +1,36 @@
+/* mpi-inline.c
+ *	Copyright (C) 1999 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/* put the inline functions as real functions into the lib */
+#define G10_MPI_INLINE_DECL
+
+#include "mpi-internal.h"
+
+/* always include the header becuase it is only
+ * included by mpi-internal if __GCC__ is defined but we
+ * need it here in all cases and the above definition of
+ * of the macro allows us to do so
+ */
+#include "mpi-inline.h"
+
diff --git a/mpi/mpi-inline.h b/mpi/mpi-inline.h
index 5dc6fc0a3..8c7cedb60 100644
--- a/mpi/mpi-inline.h
+++ b/mpi/mpi-inline.h
@@ -1,5 +1,5 @@
 /* mpi-inline.h  -  Internal to the Multi Precision Integers
- *	Copyright (C) 1998 Free Software Foundation, Inc.
+ *	Copyright (C) 1998, 1999 Free Software Foundation, Inc.
  *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
  *
  * This file is part of GnuPG.
@@ -30,8 +30,11 @@
 #ifndef G10_MPI_INLINE_H
 #define G10_MPI_INLINE_H
 
+#ifndef G10_MPI_INLINE_DECL
+  #define G10_MPI_INLINE_DECL  extern __inline__
+#endif
 
-extern __inline__ mpi_limb_t
+G10_MPI_INLINE_DECL  mpi_limb_t
 mpihelp_add_1( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 	       mpi_size_t s1_size, mpi_limb_t s2_limb)
 {
@@ -61,7 +64,7 @@ mpihelp_add_1( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
 
 
 
-extern __inline__ mpi_limb_t
+G10_MPI_INLINE_DECL mpi_limb_t
 mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 			       mpi_ptr_t s2_ptr, mpi_size_t s2_size)
 {
@@ -77,7 +80,7 @@ mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 }
 
 
-extern __inline__ mpi_limb_t
+G10_MPI_INLINE_DECL mpi_limb_t
 mpihelp_sub_1(mpi_ptr_t res_ptr,  mpi_ptr_t s1_ptr,
 	      mpi_size_t s1_size, mpi_limb_t s2_limb )
 {
@@ -107,7 +110,7 @@ mpihelp_sub_1(mpi_ptr_t res_ptr,  mpi_ptr_t s1_ptr,
 
 
 
-extern __inline__ mpi_limb_t
+G10_MPI_INLINE_DECL   mpi_limb_t
 mpihelp_sub( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
 				mpi_ptr_t s2_ptr, mpi_size_t s2_size)
 {
diff --git a/mpi/mpih-add.c b/mpi/mpih-add.c
deleted file mode 100644
index d6b0c3eb0..000000000
--- a/mpi/mpih-add.c
+++ /dev/null
@@ -1,88 +0,0 @@
-/* mpihelp-add.c  -  MPI helper functions
- *	Copyright (C) 1998 Free Software Foundation, Inc.
- *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
- *
- * This file is part of GnuPG.
- *
- * GnuPG is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * GnuPG 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
- *
- * Note: This code is heavily based on the GNU MP Library.
- *	 Actually it's the same code with only minor changes in the
- *	 way the data is stored; this is to support the abstraction
- *	 of an optional secure memory allocation which may be used
- *	 to avoid revealing of sensitive data due to paging etc.
- *	 The GNU MP Library itself is published under the LGPL;
- *	 however I decided to publish this code under the plain GPL.
- */
-
-#include <config.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "mpi-internal.h"
-
-/****************
- * Add to S1_PTR with size S1_SIZE the limb S2_LIMB and
- * store the result in RES_PTR. Return the carry
- * S1_SIZE must be > 0.
- */
-#ifndef __GNUC__
-/*_EXTERN_INLINE */
-mpi_limb_t
-mpihelp_add_1( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
-	       mpi_size_t s1_size, mpi_limb_t s2_limb)
-{
-    mpi_limb_t x;
-
-    x = *s1_ptr++;
-    s2_limb += x;
-    *res_ptr++ = s2_limb;
-    if( s2_limb < x ) { /* sum is less than the left operand: handle carry */
-	while( --s1_size ) {
-	    x = *s1_ptr++ + 1;	/* add carry */
-	    *res_ptr++ = x;	/* and store */
-	    if( x )		/* not 0 (no overflow): we can stop */
-		goto leave;
-	}
-	return 1; /* return carry (size of s1 to small) */
-    }
-
-  leave:
-    if( res_ptr != s1_ptr ) { /* not the same variable */
-	mpi_size_t i;	       /* copy the rest */
-	for( i=0; i < s1_size-1; i++ )
-	    res_ptr[i] = s1_ptr[i];
-    }
-    return 0; /* no carry */
-}
-
-
-
-/*_EXTERN_INLINE*/
-mpi_limb_t
-mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
-			       mpi_ptr_t s2_ptr, mpi_size_t s2_size)
-{
-    mpi_limb_t cy = 0;
-
-    if( s2_size )
-	cy = mpihelp_add_n( res_ptr, s1_ptr, s2_ptr, s2_size );
-
-    if( s1_size - s2_size )
-	cy = mpihelp_add_1( res_ptr + s2_size, s1_ptr + s2_size,
-			    s1_size - s2_size, cy);
-    return cy;
-}
-#endif
diff --git a/mpi/mpih-sub.c b/mpi/mpih-sub.c
deleted file mode 100644
index 7bfcddeae..000000000
--- a/mpi/mpih-sub.c
+++ /dev/null
@@ -1,81 +0,0 @@
-/* mpihelp-sub.c  -  MPI helper functions
- *	Copyright (C) 1998 Free Software Foundation, Inc.
- *	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
- *
- * This file is part of GnuPG.
- *
- * GnuPG is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * GnuPG 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
- *
- * Note: This code is heavily based on the GNU MP Library.
- *	 Actually it's the same code with only minor changes in the
- *	 way the data is stored; this is to support the abstraction
- *	 of an optional secure memory allocation which may be used
- *	 to avoid revealing of sensitive data due to paging etc.
- *	 The GNU MP Library itself is published under the LGPL;
- *	 however I decided to publish this code under the plain GPL.
- */
-
-#include <config.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "mpi-internal.h"
-
-#ifndef __GNUC__
-mpi_limb_t
-mpihelp_sub_1(mpi_ptr_t res_ptr,  mpi_ptr_t s1_ptr,
-	      mpi_size_t s1_size, mpi_limb_t s2_limb )
-{
-    mpi_limb_t x;
-
-    x = *s1_ptr++;
-    s2_limb = x - s2_limb;
-    *res_ptr++ = s2_limb;
-    if( s2_limb > x ) {
-	while( --s1_size ) {
-	    x = *s1_ptr++;
-	    *res_ptr++ = x - 1;
-	    if( x )
-		goto leave;
-	}
-	return 1;
-    }
-
-  leave:
-    if( res_ptr != s1_ptr ) {
-	mpi_size_t i;
-	for( i=0; i < s1_size-1; i++ )
-	    res_ptr[i] = s1_ptr[i];
-    }
-    return 0;
-}
-
-
-mpi_limb_t
-mpihelp_sub( mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
-				mpi_ptr_t s2_ptr, mpi_size_t s2_size)
-{
-    mpi_limb_t cy = 0;
-
-    if( s2_size )
-	cy = mpihelp_sub_n(res_ptr, s1_ptr, s2_ptr, s2_size);
-
-    if( s1_size - s2_size )
-	cy = mpihelp_sub_1(res_ptr + s2_size, s1_ptr + s2_size,
-				      s1_size - s2_size, cy);
-    return cy;
-}
-#endif
-
diff --git a/util/errors.c b/util/errors.c
index 3e9dbcf79..0590f8ed8 100644
--- a/util/errors.c
+++ b/util/errors.c
@@ -99,6 +99,7 @@ g10_errstr( int err )
       X(INVALID_URI    ,N_("unsupported URI"))
       X(NETWORK        ,N_("network error"))
       X(SELFTEST_FAILED,"selftest failed")
+      X(NOT_ENCRYPTED  ,N_("not encrypted"))
       default: p = buf; sprintf(buf, "g10err=%d", err); break;
     }
   #undef X