diff --git a/g10/free-packet.c b/g10/free-packet.c
index 0f8e0e8ce..e772c0866 100644
--- a/g10/free-packet.c
+++ b/g10/free-packet.c
@@ -1,567 +1,573 @@
 /* free-packet.c - cleanup stuff for packets
  * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
  *               2005  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 3 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, see <http://www.gnu.org/licenses/>.
  */
 
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
 
 #include "packet.h"
 #include "iobuf.h"
 #include "mpi.h"
 #include "util.h"
 #include "cipher.h"
 #include "memory.h"
 #include "options.h"
 
 void
 free_symkey_enc( PKT_symkey_enc *enc )
 {
     xfree(enc);
 }
 
 void
 free_pubkey_enc( PKT_pubkey_enc *enc )
 {
     int n, i;
     n = pubkey_get_nenc( enc->pubkey_algo );
     if( !n )
 	mpi_free(enc->data[0]);
     for(i=0; i < n; i++ )
 	mpi_free( enc->data[i] );
     xfree(enc);
 }
 
 void
 free_seckey_enc( PKT_signature *sig )
 {
   int n, i;
 
   n = pubkey_get_nsig( sig->pubkey_algo );
   if( !n )
     mpi_free(sig->data[0]);
   for(i=0; i < n; i++ )
     mpi_free( sig->data[i] );
 
   xfree(sig->revkey);
   xfree(sig->hashed);
   xfree(sig->unhashed);
 
   if (sig->pka_info)
     {
       xfree (sig->pka_info->uri);
       xfree (sig->pka_info);
     }
 
   xfree(sig);
 }
 
 
 void
 release_public_key_parts( PKT_public_key *pk )
 {
     int n, i;
     n = pubkey_get_npkey( pk->pubkey_algo );
     if( !n )
 	mpi_free(pk->pkey[0]);
     for(i=0; i < n; i++ ) {
 	mpi_free( pk->pkey[i] );
 	pk->pkey[i] = NULL;
     }
     if (pk->prefs) {
         xfree (pk->prefs);
         pk->prefs = NULL;
     }
     if (pk->user_id) {
         free_user_id (pk->user_id);
         pk->user_id = NULL;
     }
     if (pk->revkey) {
         xfree(pk->revkey);
 	pk->revkey=NULL;
 	pk->numrevkeys=0;
     }
 }
 
 
 void
 free_public_key( PKT_public_key *pk )
 {
     release_public_key_parts( pk );
     xfree(pk);
 }
 
 
 static subpktarea_t *
 cp_subpktarea (subpktarea_t *s )
 {
     subpktarea_t *d;
 
     if( !s )
 	return NULL;
     d = xmalloc (sizeof (*d) + s->size - 1 );
     d->size = s->size;
     d->len = s->len;
     memcpy (d->data, s->data, s->len);
     return d;
 }
 
 /*
  * Return a copy of the preferences 
  */
 prefitem_t *
 copy_prefs (const prefitem_t *prefs)
 {
     size_t n;
     prefitem_t *new;
 
     if (!prefs)
         return NULL;
     
     for (n=0; prefs[n].type; n++)
         ;
     new = xmalloc ( sizeof (*new) * (n+1));
     for (n=0; prefs[n].type; n++) {
         new[n].type = prefs[n].type;
         new[n].value = prefs[n].value;
     }
     new[n].type = PREFTYPE_NONE;
     new[n].value = 0;
 
     return new;
 }
 
 
 PKT_public_key *
 copy_public_key ( PKT_public_key *d, PKT_public_key *s)
 {
     int n, i;
 
     if( !d )
 	d = xmalloc(sizeof *d);
     memcpy( d, s, sizeof *d );
     d->user_id = scopy_user_id (s->user_id);
     d->prefs = copy_prefs (s->prefs);
     n = pubkey_get_npkey( s->pubkey_algo );
     if( !n )
 	d->pkey[0] = mpi_copy(s->pkey[0]);
     else {
 	for(i=0; i < n; i++ )
 	    d->pkey[i] = mpi_copy( s->pkey[i] );
     }
     if( !s->revkey && s->numrevkeys )
         BUG();
     if( s->numrevkeys ) {
         d->revkey = xmalloc(sizeof(struct revocation_key)*s->numrevkeys);
         memcpy(d->revkey,s->revkey,sizeof(struct revocation_key)*s->numrevkeys);
     }
     else
         d->revkey = NULL;
     return d;
 }
 
 /****************
  * Replace all common parts of a sk by the one from the public key.
  * This is a hack and a better solution will be to just store the real secret
  * parts somewhere and don't duplicate all the other stuff.
  */
 void
 copy_public_parts_to_secret_key( PKT_public_key *pk, PKT_secret_key *sk )
 {
     sk->expiredate  = pk->expiredate;     
     sk->pubkey_algo = pk->pubkey_algo;    
     sk->pubkey_usage= pk->pubkey_usage;
     sk->req_usage   = pk->req_usage;
     sk->req_algo    = pk->req_algo;
     sk->has_expired = pk->has_expired;    
     sk->is_revoked  = pk->is_revoked;     
     sk->is_valid    = pk->is_valid;    
     sk->main_keyid[0]= pk->main_keyid[0];
     sk->main_keyid[1]= pk->main_keyid[1];
     sk->keyid[0]    = pk->keyid[0];
     sk->keyid[1]    = pk->keyid[1];
 }
 
 
 static pka_info_t *
 cp_pka_info (const pka_info_t *s)
 {
   pka_info_t *d = xmalloc (sizeof *s + strlen (s->email));
   
   d->valid = s->valid;
   d->checked = s->checked;
   d->uri = s->uri? xstrdup (s->uri):NULL;
   memcpy (d->fpr, s->fpr, sizeof s->fpr);
   strcpy (d->email, s->email);
   return d;
 }
 
 
 PKT_signature *
 copy_signature( PKT_signature *d, PKT_signature *s )
 {
     int n, i;
 
     if( !d )
 	d = xmalloc(sizeof *d);
     memcpy( d, s, sizeof *d );
     n = pubkey_get_nsig( s->pubkey_algo );
     if( !n )
 	d->data[0] = mpi_copy(s->data[0]);
     else {
 	for(i=0; i < n; i++ )
 	    d->data[i] = mpi_copy( s->data[i] );
     }
     d->pka_info = s->pka_info? cp_pka_info (s->pka_info) : NULL;
     d->hashed = cp_subpktarea (s->hashed);
     d->unhashed = cp_subpktarea (s->unhashed);
     if(s->numrevkeys)
       {
 	d->revkey=NULL;
 	d->numrevkeys=0;
 	parse_revkeys(d);
       }
     return d;
 }
 
 
 /*
  * shallow copy of the user ID
  */
 PKT_user_id *
 scopy_user_id (PKT_user_id *s)
 {
     if (s)
         s->ref++;
     return s;
 }
 
 
 
 void
 release_secret_key_parts( PKT_secret_key *sk )
 {
     int n, i;
 
     n = pubkey_get_nskey( sk->pubkey_algo );
     if( !n )
 	mpi_free(sk->skey[0]);
     for(i=0; i < n; i++ ) {
 	mpi_free( sk->skey[i] );
 	sk->skey[i] = NULL;
     }
 }
 
 void
 free_secret_key( PKT_secret_key *sk )
 {
     release_secret_key_parts( sk );
     xfree(sk);
 }
 
 PKT_secret_key *
 copy_secret_key( PKT_secret_key *d, PKT_secret_key *s )
 {
     int n, i;
 
     if( !d )
 	d = xmalloc_secure(sizeof *d);
     else
         release_secret_key_parts (d);
     memcpy( d, s, sizeof *d );
     n = pubkey_get_nskey( s->pubkey_algo );
     if( !n )
   	d->skey[0] = mpi_copy(s->skey[0]);
     else {
 	for(i=0; i < n; i++ )
   	    d->skey[i] = mpi_copy( s->skey[i] );
     }
 
     return d;
 }
 
 void
 free_comment( PKT_comment *rem )
 {
     xfree(rem);
 }
 
 void
 free_attributes(PKT_user_id *uid)
 {
   xfree(uid->attribs);
   xfree(uid->attrib_data);
 
   uid->attribs=NULL;
   uid->attrib_data=NULL;
   uid->attrib_len=0;
 }
 
 void
 free_user_id (PKT_user_id *uid)
 {
     assert (uid->ref > 0);
     if (--uid->ref)
         return;
 
     free_attributes(uid);
     xfree (uid->prefs);
     xfree (uid->namehash);
     xfree (uid);
 }
 
 void
 free_compressed( PKT_compressed *zd )
 {
     if( zd->buf ) { /* have to skip some bytes */
 	/* don't have any information about the length, so
 	 * we assume this is the last packet */
 	while( iobuf_read( zd->buf, NULL, 1<<30 ) != -1 )
 	    ;
     }
     xfree(zd);
 }
 
 void
 free_encrypted( PKT_encrypted *ed )
 {
     if( ed->buf ) { /* have to skip some bytes */
 	if( ed->is_partial ) {
 	    while( iobuf_read( ed->buf, NULL, 1<<30 ) != -1 )
 		;
 	}
 	else {
 	   while( ed->len ) { /* skip the packet */
 	       int n = iobuf_read( ed->buf, NULL, ed->len );
 	       if( n == -1 )
 		   ed->len = 0;
 	       else
 		   ed->len -= n;
 	   }
 	}
     }
     xfree(ed);
 }
 
 
 void
 free_plaintext( PKT_plaintext *pt )
 {
     if( pt->buf ) { /* have to skip some bytes */
 	if( pt->is_partial ) {
 	    while( iobuf_read( pt->buf, NULL, 1<<30 ) != -1 )
 		;
 	}
 	else {
 	   while( pt->len ) { /* skip the packet */
 	       int n = iobuf_read( pt->buf, NULL, pt->len );
 	       if( n == -1 )
 		   pt->len = 0;
 	       else
 		   pt->len -= n;
 	   }
 	}
     }
     xfree(pt);
 }
 
 /****************
  * Free the packet in pkt.
  */
 void
 free_packet( PACKET *pkt )
 {
     if( !pkt || !pkt->pkt.generic )
 	return;
 
     if( DBG_MEMORY )
 	log_debug("free_packet() type=%d\n", pkt->pkttype );
 
     switch( pkt->pkttype ) {
       case PKT_SIGNATURE:
 	free_seckey_enc( pkt->pkt.signature );
 	break;
       case PKT_PUBKEY_ENC:
 	free_pubkey_enc( pkt->pkt.pubkey_enc );
 	break;
       case PKT_SYMKEY_ENC:
 	free_symkey_enc( pkt->pkt.symkey_enc );
 	break;
       case PKT_PUBLIC_KEY:
       case PKT_PUBLIC_SUBKEY:
 	free_public_key( pkt->pkt.public_key );
 	break;
       case PKT_SECRET_KEY:
       case PKT_SECRET_SUBKEY:
 	free_secret_key( pkt->pkt.secret_key );
 	break;
       case PKT_COMMENT:
 	free_comment( pkt->pkt.comment );
 	break;
       case PKT_USER_ID:
 	free_user_id( pkt->pkt.user_id );
 	break;
       case PKT_COMPRESSED:
 	free_compressed( pkt->pkt.compressed);
 	break;
       case PKT_ENCRYPTED:
       case PKT_ENCRYPTED_MDC:
 	free_encrypted( pkt->pkt.encrypted );
 	break;
       case PKT_PLAINTEXT:
 	free_plaintext( pkt->pkt.plaintext );
 	break;
       default:
 	xfree( pkt->pkt.generic );
 	break;
     }
     pkt->pkt.generic = NULL;
 }
 
 /****************
  * returns 0 if they match.
  */
 int
 cmp_public_keys( PKT_public_key *a, PKT_public_key *b )
 {
     int n, i;
 
     if( a->timestamp != b->timestamp )
 	return -1;
     if( a->version < 4 && a->expiredate != b->expiredate )
 	return -1;
     if( a->pubkey_algo != b->pubkey_algo )
 	return -1;
 
     n = pubkey_get_npkey( b->pubkey_algo );
-    if( !n )
-	return -1; /* can't compare due to unknown algorithm */
-    for(i=0; i < n; i++ ) {
-	if( mpi_cmp( a->pkey[i], b->pkey[i] ) )
+    if( !n ) { /* unknown algorithm, rest is in opaque MPI */
+	if( mpi_cmp( a->pkey[0], b->pkey[0] ) )
 	    return -1;
+    } else {
+	for(i=0; i < n; i++ ) {
+	    if( mpi_cmp( a->pkey[i], b->pkey[i] ) )
+		return -1;
+	}
     }
 
     return 0;
 }
 
 /****************
  * Returns 0 if they match.
  * We only compare the public parts.
  */
 int
 cmp_secret_keys( PKT_secret_key *a, PKT_secret_key *b )
 {
     int n, i;
 
     if( a->timestamp != b->timestamp )
 	return -1;
     if( a->version < 4 && a->expiredate != b->expiredate )
 	return -1;
     if( a->pubkey_algo != b->pubkey_algo )
 	return -1;
 
     n = pubkey_get_npkey( b->pubkey_algo );
-    if( !n )
-	return -1; /* can't compare due to unknown algorithm */
-    for(i=0; i < n; i++ ) {
-	if( mpi_cmp( a->skey[i], b->skey[i] ) )
+    if( !n ) { /* unknown algorithm, rest is in opaque MPI */
+	if( mpi_cmp( a->skey[0], b->skey[0] ) )
 	    return -1;
+    } else {
+	for(i=0; i < n; i++ ) {
+	    if( mpi_cmp( a->skey[i], b->skey[i] ) )
+		return -1;
+	}
     }
 
     return 0;
 }
 
 /****************
  * Returns 0 if they match.
  */
 int
 cmp_public_secret_key( PKT_public_key *pk, PKT_secret_key *sk )
 {
     int n, i;
 
     if( pk->timestamp != sk->timestamp )
 	return -1;
     if( pk->version < 4 && pk->expiredate != sk->expiredate )
 	return -1;
     if( pk->pubkey_algo != sk->pubkey_algo )
 	return -1;
 
     n = pubkey_get_npkey( pk->pubkey_algo );
     if( !n )
 	return -1; /* can't compare due to unknown algorithm */
     for(i=0; i < n; i++ ) {
 	if( mpi_cmp( pk->pkey[i] , sk->skey[i] ) )
 	    return -1;
     }
     return 0;
 }
 
 
 
 int
 cmp_signatures( PKT_signature *a, PKT_signature *b )
 {
     int n, i;
 
     if( a->keyid[0] != b->keyid[0] )
 	return -1;
     if( a->keyid[1] != b->keyid[1] )
 	return -1;
     if( a->pubkey_algo != b->pubkey_algo )
 	return -1;
 
     n = pubkey_get_nsig( a->pubkey_algo );
     if( !n )
 	return -1; /* can't compare due to unknown algorithm */
     for(i=0; i < n; i++ ) {
 	if( mpi_cmp( a->data[i] , b->data[i] ) )
 	    return -1;
     }
     return 0;
 }
 
 
 /****************
  * Returns: true if the user ids do not match
  */
 int
 cmp_user_ids( PKT_user_id *a, PKT_user_id *b )
 {
     int res=1;
 
     if( a == b )
         return 0;
 
     if( a->attrib_data && b->attrib_data )
       {
 	res = a->attrib_len - b->attrib_len;
 	if( !res )
 	  res = memcmp( a->attrib_data, b->attrib_data, a->attrib_len );
       }
     else if( !a->attrib_data && !b->attrib_data )
       {
 	res = a->len - b->len;
 	if( !res )
 	  res = memcmp( a->name, b->name, a->len );
       }
 
     return res;
 }
diff --git a/mpi/mpi-cmp.c b/mpi/mpi-cmp.c
index e119fad04..3c1322a10 100644
--- a/mpi/mpi-cmp.c
+++ b/mpi/mpi-cmp.c
@@ -1,73 +1,89 @@
 /* mpi-cmp.c  -  MPI functions
  * Copyright (C) 1998, 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 3 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, see <http://www.gnu.org/licenses/>.
  */
 
 #include <config.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include "mpi-internal.h"
 
 int
 mpi_cmp_ui( MPI u, unsigned long v )
 {
     mpi_limb_t limb = v;
 
     mpi_normalize( u );
     if( !u->nlimbs && !limb )
 	return 0;
     if( u->sign )
 	return -1;
     if( u->nlimbs > 1 )
 	return 1;
 
     if( u->d[0] == limb )
 	return 0;
     else if( u->d[0] > limb )
 	return 1;
     else
 	return -1;
 }
 
 int
 mpi_cmp( MPI u, MPI v )
 {
     mpi_size_t usize, vsize;
     int cmp;
 
+    if (mpi_is_opaque (u) || mpi_is_opaque (v))
+      {
+	if (mpi_is_opaque (u) && !mpi_is_opaque (v))
+	  return -1;
+	if (!mpi_is_opaque (u) && mpi_is_opaque (v))
+	  return 1;
+	if (!u->nbits && !v->nbits)
+	  return 0; /* Empty buffers are identical.  */
+	if (u->nbits < v->nbits)
+	  return -1;
+	if (u->nbits > v->nbits)
+	  return 1;
+	return memcmp (u->d, v->d, u->nbits);
+      }
+
     mpi_normalize( u );
     mpi_normalize( v );
     usize = u->nlimbs;
     vsize = v->nlimbs;
     if( !u->sign && v->sign )
 	return 1;
     if( u->sign && !v->sign )
 	return -1;
     if( usize != vsize && !u->sign && !v->sign )
 	return usize - vsize;
     if( usize != vsize && u->sign && v->sign )
 	return vsize + usize;
     if( !usize )
 	return 0;
     if( !(cmp=mpihelp_cmp( u->d, v->d, usize )) )
 	return 0;
     if( (cmp < 0?1:0) == (u->sign?1:0))
 	return 1;
     return -1;
 }