diff --git a/src/zlevis b/src/zlevis
index fc9b701..85a6733 100755
--- a/src/zlevis
+++ b/src/zlevis
@@ -15,21 +15,23 @@ fi
 # Display usage information if input is from a terminal
 if [ -t 0 ]; then
     exec >&2
-    echo "Usage: zlevis {decrypt|encrypt} {pool|*} [options]"
+    echo "Usage: \"zlevis {decrypt|encrypt} {pool|key} [options]\""
     exit 2
 fi
 
 case "$1" in
     decrypt) 
-        case "$2" in 
+        case "$2" in
             pool) zfs list -Ho tpm:jwe $3 | zlevis-decrypt;;
-            *) zlevis-decrypt $2;;
+            key) zlevis-decrypt;;
+            *) exit 1;;
         esac
     ;;
     encrypt)
         case "$2" in
             pool) read -r -d . key || zfs set tpm:jwe=$(printf "%s" "$key" | zlevis-encrypt $4) $3;;
-            *) zlevis-encrypt $2;;
+            key) zlevis-encrypt $3;;
+            *) exit 1;;
         esac
     ;;
     *) exit 1;;