hyperchaos image encryption algorithm VPN

According to the chaotic dimension, the chaos-based image encryption algorithms mainly include three types [45-51]: (1) the low-dimensional chaos-based image encryption algorithm; (2) the hyperchaos image encryption algorithm; and (3) the image encryption based on the compound of the other encryption algorithm and chaos.A lot of chaos-based image encryption algorithms use low-dimension chaos as the encryption tools [52,53]. Although these algorithms are simple and effective to some extent, many of them are very disappointing. Some of the reasons are as follows. Firstly, because of the dynamical degradation of chaotic systems in their realization with a digital computer, the security is low. Secondly, some low-dimension chaos-based encryptions have slow performance speeds because of analytical floating-point computations, which make the encryptions infeasible in real time. Moreover, if chaotic systems with simple constructions are directly used to encrypt an image, the useful information can be extracted from the chaotic orbits. To overcome these drawbacks, hyperchaos systems have been proposed to overcome these problems.