diff --git a/ChangeLog b/ChangeLog
index ef9ad8515..365af3232 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -29,6 +29,10 @@
    - djm@cvs.openbsd.org 2013/12/02 02:56:17
      [ssh-pkcs11-helper.c]
      use-after-free; bz#2175 patch from Loganaden Velvindron @ AfriNIC
+   - djm@cvs.openbsd.org 2013/12/02 03:09:22
+     [key.c]
+     make key_to_blob() return a NULL blob on failure; part of
+     bz#2175 from Loganaden Velvindron @ AfriNIC
 
 20131121
  - (djm) OpenBSD CVS Sync
diff --git a/key.c b/key.c
index b20bcda59..3ee2d61af 100644
--- a/key.c
+++ b/key.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: key.c,v 1.105 2013/10/29 09:42:11 djm Exp $ */
+/* $OpenBSD: key.c,v 1.106 2013/12/02 03:09:22 djm Exp $ */
 /*
  * read_bignum():
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -1587,6 +1587,10 @@ to_blob(const Key *key, u_char **blobp, u_int *lenp, int force_plain)
 	Buffer b;
 	int len, type;
 
+	if (blobp != NULL)
+		*blobp = NULL;
+	if (lenp != NULL)
+		*lenp = 0;
 	if (key == NULL) {
 		error("key_to_blob: key == NULL");
 		return 0;