diff --git a/ChangeLog b/ChangeLog
index 87b6d1266..fade46942 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -50,6 +50,9 @@
    - markus@cvs.openbsd.org 2002/03/18 17:16:38
      [packet.c packet.h]
      export/import cipher state, iv and ssh2 seqnr; needed by ssh-privsep
+   - markus@cvs.openbsd.org 2002/03/18 17:23:31
+     [key.c key.h]
+     add key_demote() for ssh-privsep
 
 20020317
  - (tim) [configure.ac] Assume path given with --with-pid-dir=PATH is wanted,
@@ -7896,4 +7899,4 @@
  - Wrote replacements for strlcpy and mkdtemp
  - Released 1.0pre1
 
-$Id: ChangeLog,v 1.1939 2002/03/22 01:42:04 mouring Exp $
+$Id: ChangeLog,v 1.1940 2002/03/22 01:45:53 mouring Exp $
diff --git a/key.c b/key.c
index cda91571a..51902ea25 100644
--- a/key.c
+++ b/key.c
@@ -32,7 +32,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include "includes.h"
-RCSID("$OpenBSD: key.c,v 1.41 2002/02/28 15:46:33 markus Exp $");
+RCSID("$OpenBSD: key.c,v 1.42 2002/03/18 17:23:31 markus Exp $");
 
 #include <openssl/evp.h>
 
@@ -801,3 +801,46 @@ key_verify(
 		break;
 	}
 }
+
+/* Converts a private to a public key */
+
+Key *
+key_demote(Key *k)
+{
+	Key *pk;
+	
+	pk = xmalloc(sizeof(*pk));
+	pk->type = k->type;
+	pk->flags = k->flags;
+	pk->dsa = NULL;
+	pk->rsa = NULL;
+
+	switch (k->type) {
+	case KEY_RSA1:
+	case KEY_RSA:
+		if ((pk->rsa = RSA_new()) == NULL)
+			fatal("key_demote: RSA_new failed");
+		if ((pk->rsa->e = BN_dup(k->rsa->e)) == NULL)
+			fatal("key_demote: BN_dup failed");
+		if ((pk->rsa->n = BN_dup(k->rsa->n)) == NULL)
+			fatal("key_demote: BN_dup failed");
+		break;
+	case KEY_DSA:
+		if ((pk->dsa = DSA_new()) == NULL)
+			fatal("key_demote: DSA_new failed");
+		if ((pk->dsa->p = BN_dup(k->dsa->p)) == NULL)
+			fatal("key_demote: BN_dup failed");
+		if ((pk->dsa->q = BN_dup(k->dsa->q)) == NULL)
+			fatal("key_demote: BN_dup failed");
+		if ((pk->dsa->g = BN_dup(k->dsa->g)) == NULL)
+			fatal("key_demote: BN_dup failed");
+		if ((pk->dsa->pub_key = BN_dup(k->dsa->pub_key)) == NULL)
+			fatal("key_demote: BN_dup failed");
+		break;
+	default:
+		fatal("key_free: bad key type %d", k->type);
+		break;
+	}
+
+	return (pk);
+}
diff --git a/key.h b/key.h
index a2257731a..8d1fa4126 100644
--- a/key.h
+++ b/key.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: key.h,v 1.18 2002/02/24 19:14:59 markus Exp $	*/
+/*	$OpenBSD: key.h,v 1.19 2002/03/18 17:23:31 markus Exp $	*/
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -58,6 +58,7 @@ struct Key {
 Key	*key_new(int);
 Key	*key_new_private(int);
 void	 key_free(Key *);
+Key	*key_demote(Key *);
 int	 key_equal(Key *, Key *);
 char	*key_fingerprint(Key *, enum fp_type, enum fp_rep);
 char	*key_type(Key *);