The chaos-based encryption VPN

The chaos-based encryption [33] was first proposed in 1989. Since then, a lot of chaos-based encryption algorithms have been proposed by the researchers. These works all make use of the chaotic properties such as the sensitive dependence on initial conditions and system parameters, pseudo-random property, nonperiodicity, topological transitivity, etc. In 1997, Fridrich [34] first applied the chaos-based encryption to encrypt an image.The principle of chaos-based image encryption [34-37] is that some operations are performed between the original information and chaotic sequence that is generated by the chaotic generator, and the original information becomes similar to the random noise. Thereby, the encryption aim is accomplished. Figure 2 shows the encryption and decryption processes in detail. Firstly, the sender selects a secret key and uses a specifically chaotic sign generator to generate a chaotic signal sequence stream. Then, the original image information is confused or diffused in light of the chaotic sequence and the encrypted image becomes similar to the random noise generated. Decryption is basically the same as encryption, and the right-half of Figure 2 shows the decryption process.