An electronic locking device having a key unit and lock unit which units each have substantially identical integrated circuits contained therein for electronically controlling the operation of the locking device. The integrated circuit in the key element is adapted to transmit a stream of pulses into a plurality of trains of pulses upon insertion of the key unit into the lock unit. Each train of pulses is of a predetermined length. The integrated circuit in the lock unit is adapted to receive the train of pulses emitted from the key unit, to determine the length of the train of pulses, and compare the length of the train of pulses received to determine whether such train length coincides with the predetermined length. The integrated circuit in the lock unit will then emit a signal to allow the lock unit to open. If the length of the train of pulses does not coincide with the predetermined length, the lock unit integrated circuit will not emit a signal and the locking device will remain locked. Details of mechanical lock structures are also disclosed, with such locks providing dead bolt protection and autolock operation; the locks are adapted to be actuated with minimal energy consumption.