Abstract
Image encryption is one of the sensitive areas used recently to save information over the Internet and confirms the security on a higher level. A new cryptosystem has been proposed for the encoding and decoding of images using sine map, chaotic tent map, and circulant matrices. The process involves three stages. The sine map is used for the permutation phase. In the substitution phase, the Hill cipher method together with prime circulant matrix are used and a chaotic tent map is used in the diffusion phase. The algorithm becomes impenetrable to resist differential- and statistical-type attacks. The algorithm's key space is sufficient in size to withstand brute-force attacks. This symmetric image encryption algorithm indicates good results for correlation analysis, key space analysis, entropy analysis, key sensitivity analysis, histogram analysis, number of pixel change rate (NPCR), unified average changing intensity (UACI), and peak signal-to-noise ratio (PSNR). From all these simulation results, we come to know that the constructed image encryption cryptosystem is systematic and vigorous, supplying better protection for image encryption.