Electronic key system using alpha detection

We have developed the new electronic key system utilizes random pulse from alpha-particle detection with PIN photo diode. The random pulse by natural decay of alpha source is stable under the every outside environment like as temperature, pressure, an electromagnetic wave, and so on. The stable and un-predicted signals of the random pulses are the most suitable as a source of authentication signal for the electric key system. The program made of manufacture side forms the key code under current electronic key. Therefore, the manufacture must keep the code data secret for long time. The new electronic key always identify between key body and each key by the original pulse data from alpha particles. It is reduce the control cost of security remarkably. Moreover, back ground noise can be ignored in the circuit and it doesn't need to enlarge a total number of activity. The activity of the alpha source is about 10-100 Bq in one module. (author)