Develop Security of Non-linear Stream Cipher System Based on Adder


The strength of stream cipher system depends on the strength of keystream generator. The generator generates pseudo-random-sequence which passes randomness tests. Non-linear stream cipher based on Adder has a number of shortages. This weakness is failure of randomness tests and success of correlation attacks. In this paper, Adder is developed by inserting a third shift register. It leads to improve the generator to pass randomness tests. Also, the non-linear complexity is increased and correlation attack is faced.