A Kind Of Interactive Pseudo-random Sequence Generator Algorithm Design

Stream cipher is widely used in the fileds of miliatry and civilian area. In secret communication, in order to improve the ablity against attack, key stream sequences are required to have three properities:long period;large linear complexity;unpredicatability. The main task of stream cipher is to design a key stream generator, to find pseudorandom sequences with good properties, having large amount of codes and easy to produce. In this thesis, we focus on the construction of key stream generator, properties and testing methods of pseudorandom sequences.The main works and conculsions are described as follows:A cross arrangement-interactive generators based on principle of clock-controlled is designed. This generator is consist of four LFSRs, two of them as clock controlling sequences,the others as controlled sequences,and they are mutually controlled. The period, the lower bound of complexity,0-1balance,run test, correlational function are discussed. The results shows that the statistical properties of the new generator model are better than mutual clock-controlled generator. Conbining the mutual clock-controlled generator and clock-controlled alternating step generator, taking⊕in the end-interactive generators is designed. This generator is consist of four LFSRs,here using the alternating step pattern to controll the clock-contorlled sequences. The period, complexity and other properties of the generator are discussed. The linear complexity of proposed generator is proved based on principle of sampling sequence. The results shows that the period, complexity of the new generator are better than mutual clock-controlled generator and clock-controlled alternating step generator.