A locking system that controls access to a parcel storage box having a lockable door or lid with an electrically controllable locking mechanism. The locking system includes an optical scanner for scanning a barcode on a parcel that includes tracking information. A communication module transmits the tracking information to a separate computing system over a wireless network and then receives a response from the computing system indicating whether or not the transmitted barcode information is associated with an expected delivery. Electrical circuitry opens the locking mechanism if the tracking information is associated with an expected delivery.