A proposed Development of Clock Control Stream Cipher based on Suitable Attack

The feedback shift registers (FSR) is known to allow produce sequences with large period and fast realization. It is well known that building block used for constructing a key-stream generator, consists of a control register CR and a clock-controlled generating register (GR). The estimation of the sequence period generated by a clock-controlled (LFSR) with an irreducible feedback polynomial and an arbitrary structure of the control sequence is an important aspect in the stream cipher design. This paper offers attacks on stream cipher and concentrate on the algebraic attack because it represents the most important one among the other types of attacks. Also, the paper presents developed clock control sequence generator based on combiner with an increase in the complexity of the structure.