A novel bit-level image encryption algorithm based on 2D-LICM hyperchaotic map

- The 2D-LICM hyperchaotic map is firstly proposed based on cascade modulation couple model. It has better ergodicity, random and larger complexity than some existing chaotic maps.
- Based on this map, a novel image encryption algorithm is designed by employing bit-level confusion and diffusion simultaneously.
- The obtained ciphertext is used to update the initial values of chaotic system real time in bit-level to improve the ability of resisting known plaintext attack and chosen plaintext attack.
- Results show that this algorithm has higher security and lower computation and time complexity compared with exiting algorithms. It has wider application prospect.

In this paper, a new two-dimensional Logistic ICMIC cascade map (2D-LICM) is proposed based on cascade modulation couple (CMC) model. Performance evaluations show that it has hyperchaotic behavior, wide chaotic range and large complexity. Based on this map, a novel image encryption algorithm is designed by employing bit-level permutation and diffusion simultaneously. The bit-level permutation is performed by circular shifting, and the bit-level diffusion is carried out by exclusive or (xor) and reverse operations. In addition, the initial values of chaotic system are updated in real time according to the obtained ciphertext and it greatly improves the ability of resisting known plaintext attack and chosen plaintext attack. Simulation results and performance analysis show that this algorithm has good encryption effect and high efficiency. It can resist typical attacks including statistical, brute-force, differential attacks and so forth.