Improvement A5/1 encryption algorithm based on sponge techniques

A5/1 stream cipher is used in Global System for Mobile Communications (GSM) in order to provide privacy on air communication. In this paper introduce new improvements to the A5/1 stream cipher based on using new technology concepts called sponge function. Sponge functions that represent in this paper constructed based on combine between the advantage of stream cipher and hash concepts. New S-box generation is proposed to provide the dynamic features to the sponge technology in order solve the weakness that appear in majority function that used in A5/1 stream cipher by provide dynamic behavior in number of registers and transformation. According the experimental results and the compassion between the A5/1 and the proposed improvement shown the proposed algorithm will increase the randomness features for the A5/l algorithm. The output bit-stream generated by the proposed stream cipher has improved the randomness performance and provide more security to the GSM security algorithm.