Study on Chaotic Cipher with Robustness and Its Characteristics

Abstract

In this paper, we propose a robustness cryptosystem with a small amount of computation. By adopting a stream cipher not but block cipher like AES, the processing speed is improved. Furthermore, it has chaotic properties and improved randomness. Moreover, since an expression for synchronizing the encryption system and the decryption system is not used in the proposed method, even when a bit error occurs, it is correctly decrypted. In general, nonlinear signals such as chaotic map, Jacobian can be estimated from time series signals by Sano-Sawada method. In the chaotic cipher, the parameters in the expression are used as cryptography keys. Therefore, if Jacobian is a constant, the cryptographic key will be estimated. In the proposed system, we formulate the expression so that each element of Jacobian becomes time-variant as much as possible. Thereby the safety of the system is secured.