An approach for cosntruction of stream ciphers based on new type of cipher gamma generators with a non-linear (fuzzy) shift register selection function is proposed. The best configuration of generator is selected for generating a gamma whose properties are closest to white noise. It is shown that the proposed approach makes it possible to generate a gamma sequence with a quality that exceeds a number of other classical generators.

Keywords: cryptography, stream cipher, gamma, PNSG, random test, fuzzy logic,membership function, linguistic variable, defuzzification, linear feedback shift register