A Robust Color Image Encryption Algorithm in Dual Domain Using Chaotic Map

Abstract

Secure transmissions of secret images over the public network have a lot of challenges that include hacking, manipulating the actual content, destroying, etc. In order to solve these issues, various image encryption algorithm has been given by experts that work on both spatial or frequencies domain. Most of them are work with gray scale images. In this paper, a robust color image encryption technique is proposed that uses Discrete Cosine Transformation (DCT) and a diffusion operation first applied in spatial domain and then a confusion operation is applied in frequency domain, and that's why this paper has title in dual domain. In encryption, firstly the plain image is performed the XOR operation with key generated by Logistic Map, and we get the diffused image of plain image. Then diffused image is divided into fixed-size blocks and converted in frequencies domain using DCT, then chaotic map is applied to reorder the frequencies coefficient. At last, the Inverse DCT (IDCT) is applied to get the encrypted image. In order to prove the algorithm robustness, various tests has been performed and its result has been compared with existing technique. The analysis and result show that the encrypted image is enough robust against any types of attacks.