A system for use in banking operates responsive to data in data bearing records. The system is suitable for securing the contents in safety deposit boxes or similar locked receptacles, and selectively permits access to key locks only to individuals who have been determined to be authorized to have such access. Each safety deposit box or other receptacle includes a door (16) with at least one key lock (22, 24) thereon. An assembly (26) is installed on the preexisting door to limit access to a key lock to an authorized person. The assembly includes a body (32) that is held in a blocking position by a cover lock. A selectively programmable electronic key module (28) is operative to change the condition of the cover lock from a latched to an unlatched condition.