Study On The Application Of Chaotic Sequence Encryption

Chaotic systems are sensitive to initial conditions and chaotic parameters, and can produce massive high security sequence with analogous randomness, correlation, broadband and continuous spectrum. Chaotic sequences are suitable for the sequence encryption, this paper applies chaos to the cryptography and proposes chaotic sequence encryption cryptogram.Logistic map is analyzed by Lyapunov exponents and power spectrum, proving its property according with cryptology. Then the initial value and parameter is used as secret key and the Logistic map's interactive value is converted into binary sequence by fix-point algorithm that is NOR with cipher bit by bit.Due to cryptograph and control orbit correlate, according to phase space reconstruction theorem, this paper proved that utilizing continuous data can construct the control orbit function of low dimensional chaotic dynamic system thus forecasts chaotic sequence encryption is invalidated. Chaotic sequence is confined to computer's word length when it is digitized, which prevents its application. To solve those problems, this paper introduced appropriate perturbation algorithm by randomly changing the chaotic initial. Concludes from experiment proves that the method has improved the complexity of chaos, the perturbation destroyed cipher orbit correlation property, enlarged the sequence period and expanded the cryptograph space, the property of cryptograph is uniform distribution. Improved algorithm overcomes low dimensional chaotic prone to be defected and has excellent anti-broken strength for chosen plain texts ability.