THE 323's central door locking system enables the side doors and boot lid to be locked simultaneously. The side doors can be locked using the boot lid key. The engine immobiliser disables the fuel and ignition system if a thief attempts to use any key other than a Mazda key. The use of a challenge and response system makes it extremely difficult to steal the car using a duplicate key. A steering shaft declutching device prevents the steering lock from breaking if a thief applies significant torque to the steering wheel. There is no remote central locking.