--- a/certs/Makefile	Tue Sep 27 22:11:14 2016 +0100
+++ b/certs/Makefile	Thu Nov 03 23:51:40 2016 +0100
@@ -27,4 +27,4 @@
 
 %.key:
 	umask 0077 && openssl genrsa -out $@ $(keysize)
-	@chmod 400 $@ -c
+	@chmod 400 $@