ANALOG SIGNAL ENCRYPTING AND DECRYPTING SYSTEM

摘要

The encrypter of the encrypting and decrypting system samples the incoming analog signal at a constant period and delivers an encrypted signal by successive reading of the samples under the control of an encrypting signal which has a predetermined period multiple of the sampling period, The decrypter of the system performs the inverse function to reconstruct a decrypted signal analogous to the incoming signal. The encrypter and decrypter each comprises two delay lines, In the encrypter, the incoming signal is sampled and written at the sampling period during each of predetermined periods so as to fill all the stages of a delay line. Then the samples are read according the initial order at the instants of a time distribution which is predetermined by the encrypting signal and which is different from the time equidistributed writing instants. The analog encrypted signal results from at least time compressions and eventually time expansions of the incoming signal samples.