Discrete Chaotic Systems with One-Line Equilibria and Their Application to Image Encryption

This paper introduces nine four-dimensional discrete chaotic systems with one-line equilibria (DCSLE), consisting of some simple sine functions. Based on the generalized chaos synchronization (GCS) theorem, a DCSLE is used to construct an eight-dimensional DCSLE GCS system. The new DCSLE GCS system is verified by numerical simulation and then used to design a chaotic pseudorandom number generator (CPRNG). The randomness of ten 100-key streams generated by the CPRNG, two GCS-based CPRNGs, the RC4 PRNG and the ZUC PRNG are tested by the SP800-22/FIPS 140-2 tests. The test results confirm that the randomness performances of the three CPRNGs are promising, for there are no significant correlations between a keystream and any perturbed keystream generated by such CPRNG. Also, the key space of the CPRNG is larger than 2¹¹⁷⁰. Finally, the CPRNG is used with an avalanche-effect encryption scheme to encrypt an RGB image, demonstrating that the CPRNG is able to generate the avalanche effects which are similar to those generated by ideal CPRNGs.