--- a/certs/Makefile	Thu Feb 25 15:35:44 2016 +0100
+++ b/certs/Makefile	Thu Feb 25 15:36:12 2016 +0100
@@ -60,3 +60,7 @@
 %.key:
 	umask 0077 && openssl genrsa -out $@ $(keysize)
 	@chmod 400 $@ -c
+
+# Generate Diffie-Hellman parameters
+dh-%.pem:
+	openssl dhparam -out $@ $*