Analysis and Elimination of Digital Chaotic Key Sequence’s Autocorrelation

The special properties of the chaos make the chaotic encryption technology to be an important research field of information science and technology. However, because digital chaos is affected by finite precision of computer, chaos system properties present degradation—short periodicity. This paper firstly analyses reason that causes strong autocorrelation of digital chaotic sequence, then uses statistical method to deal with correlation of the sequence, and last chooses K-L transform method for eliminating correlation through comparing different methods. Simulation results prove that this method can eliminate the autocorrelation of logistic sequence, and its autocorrelation figure is similar to white Gaussian noise autocorrelation’s. Meanwhile, it also can increase the period of logistic sequence, which makes up short periodicity of digital chaotic sequence and makes digital chaotic key sequences can be applied safely to encryption system.