Edinburgh Napier University

  The evolution of wireless and mobile communication from 0G to the upcoming 5G gives riseto data sharing through the Internet. This data transfer via open public networks are susceptible to severaltypes of attacks. Encryption is a method that can protect information from hackers and hence confidentialdata can be secured through a cryptosystem. Due to the increased number of cyber attacks, encryption hasbecome an important component of modern-day communication. In this paper, a new image encryptionalgorithm is presented using chaos theory and dynamic substitution. The proposed scheme is based on twodimensional Henon, Ikeda chaotic maps, and substitution box (S-box) transformation. Through Henon, arandom S-Box is selected and the image pixel is substituted randomly. To analyze security and robustnessof the proposed algorithm, several security tests such as information entropy, histogram investigation,correlation analysis, energy, homogeneity, and mean square error are performed. The entropy values ofthe test images are greater than 7.99 and the key space of the proposed algorithm is 2^798. Furthermore, thecorrelation values of the encrypted images using the the proposed scheme are close to zero when comparedwith other conventional schemes. The number of pixel change rate (NPCR) and unified average changeintensity (UACI) for the proposed scheme are higher than 99.50% and 33, respectively. The simulationresults and comparison with the state-of-the-art algorithms prove the efficiency and security of the proposed scheme.