Cryptography based on spatiotemporal chaotic systems

Chaos has been applied in cryptography in the past decades since there are tight relationships between chaos and cryptography. Especially, spatiotemporal chaotic systems can be used to design cryptosystems with satisfactory properties. The chapter focuses on applying a typical spatiotemporal chaotic system, i.e., a coupled map lattice (CML) in cryptography. Multiple-output pseudo-random bit generators (PRBGs) based on CMLs with various constructions and parameters values are designed. Their properties are investigated and compared to determine a certain CML with certain parameters from which the resulting PRBG have satisfactory properties. Additionally, a stream cipher based on the CML is designed and analyzed. It is shown that it has high security, high efficiency and low cost. Moreover, a multimedia cryptosystem based on the proposed stream cipher is constructed by using a field programmable gate array (FPGA). The effects of the encryptions of the text file, the audio file and the image file by using the cryptosystem is measured as effective. © 2010 Springer-Verlag Berlin Heidelberg.