diff --git a/src/fileio.c b/src/fileio.c
index 1c0ac85..c7a2b74 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -2953,7 +2953,7 @@
     }
     /* When starting to edit a new file which does not have encryption, clear
      * the 'key' option, except when starting up (called with -x argument) */
-    else if (newfile && *curbuf->b_p_key && !starting)
+    else if (newfile && *curbuf->b_p_key != NUL && !starting)
 	set_option_value((char_u *)"key", 0L, (char_u *)"", OPT_LOCAL);
 
     return cryptkey;