diff --git a/keys.sh b/keys.sh
index 63166f3..76c7c33 100755
--- a/keys.sh
+++ b/keys.sh
@@ -4,6 +4,11 @@
 # Utility script for generating a private/public key pair
 #
 
+if [[ -z "$1" ]]; then
+	echo "usage: ./keys.sh [key_basename]"
+	exit 1
+fi
+
 mkdir keys
 
 openssl genrsa -out keys/$1 2048