Belazi Akram, Benrhouma Oussama, Hermassi Houcemeddine and Belghith Safya, Ecole Nationale d'Ingenieurs de Tunis (ENIT), Tunisia

Selective encryption presents a great solution to optimize time efficiency during encryption process. In this paper a novel selective encryption scheme based on DCT transform with AES algorithm is presented. In the DCT method, the basic idea is to decompose the image into 8×8 blocks and these blocks are transformed from the spatial domain to the frequency domain by the DCT. Then, the DCT coefficients correlated to the lower frequencies of the image block are encrypted. The proposed cryptosystem is evaluated using various security and statistical analysis; results show that the proposed algorithm is strong against attacks and suitable for practical application.

DCT, Selective Encryption, AES Cipher