Abstract: A simple and economical, yet tamper-proof, electronic locking apparatus for motor vehicles features an electronic key and an electronic lock, which each contain a synchronized, constantly operating, precision oscillator. The output of each oscillator is applied at a predetermined counting rate to a respective number sequence generator. Both generators contain the same predetermined number sequence, which they step through at the same clock rate, applying the instantaneous value of the count to a first input of a respective computer. A second input of each computer is connected to a fixed memory which supplies a permanent, characteristic code number to the computer. Both the count state and the characteristic code number are combined using corresponding algorithms in the key and in the lock to produce a combination code. The key-produced combination code is sent from a transmitter in the key to a receiver in the lock and compared there with the lock-produced combination code.

Abstract: Disclosed is an electronic locking device including electrically interacting key part and lock part each including electronic data processor with an inner code which is particular for a pair of key and lock units which belong one to another. To increase the number of variations and to inhibit the breaking of the code, the latter is generated in two stages whereby the input magnitudes for the code are retrieved from a collection of random numbers randomly generated in each unit. In the first stage of the coding process, the input magnitudes are subjected to computation according to a definite algorithm. In the second stage, only a fragment of the computation result is used and arranged according to a definite rule or formula to serve as output magnitudes for a comparator where the final arrangement of the fragments formed in respective units is tested as to mutual agreement. In the case of an agreement, a switching pulse is generated which activates bolt control mechanism in the locking unit.