diff --git a/scripts/secure_command.py b/scripts/secure_command.py
index e1ccd1d..a45475b 100755
--- a/scripts/secure_command.py
+++ b/scripts/secure_command.py
@@ -22,6 +22,7 @@
 parser.add_argument("--target-node", default=None, type=int, help="target node ID")
 parser.add_argument("--private-key", default=None, type=str, help="private key file")
 parser.add_argument("--bus-num", default=1, type=int, help="MAVCAN bus number")
+parser.add_argument("--signing-passphrase", help="MAVLink2 signing passphrase", default=None)
 parser.add_argument("uri", default=None, type=str, help="CAN URI")
 parser.add_argument("paramop", default=None, type=str, help="parameter operation")
 args = parser.parse_args()
@@ -50,6 +51,9 @@
 node = dronecan.make_node(args.uri, node_id=args.node_id, bitrate=args.bitrate)
 node.can_driver.set_bus(args.bus_num)
 
+if args.signing_passphrase is not None:
+    node.can_driver.set_signing_passphrase(args.signing_passphrase)
+
 # Initializing a node monitor
 node_monitor = dronecan.app.node_monitor.NodeMonitor(node)