A Partial Image Cryptosystem Based on Discrete Cosine Transform and Arnold Transform

Abstract

Partial image cryptosystem has drawn much more attention in various real time applications in order to address issue like security along with the computational overhead. Generally in the partial image cryptosystem, the encryption-decryption process is employed on the compressed version of secret image (i.e. the significant part of the secret image) for reducing the computational overhead. In this paper, we have proposed a partial image cryptosystem for uncompressed color image where the discrete cosine transform is employed on each color components of the color image to select the significant coefficients and subsequently the selected coefficients of the color image are fed into encryption process for reducing the computational overhead. In encryption process, the selected coefficients are confused using Arnold transform followed by diffusion with keys. After completion of the encryption process, unencrypted coefficients are appended with encrypted components to form the uncompressed encrypted image. The proposed scheme has been tested on a set of standard color test images and satisfactory results have been found. In addition, the simulation results show the effectiveness of the proposed image cryptosystem in terms of security analysis.