An Approach for Image Encryption / Decryption Based on Quaternion Fourier Transform

The image encryption or the secure image processing is an art of handling the image to provide protection from those image information theft or damage. It is necessary to maintain security for images such as medical, military, etc. So far many research work have been developed in the field of image information security and prevention. However the achieved level of security is not satisfactory, thus still this field is in research to find a better solution for the image data security and prevention. In this sense, this research is targeted to develop a better strategy for the image data prevention and security enhancement. There are many cryptography technique is available in the technical world, however this work adapted quaternion based approach for the image data security. Qua-ternion is a kind of number notation, it is the combination of both scalar and vector. Quaternion rotation is the concept applied in the image encryption for the security purpose. In the existing works authors have applied the Quaternion rotation based encryption of medical image and color images. In order to further enhance the performance of encryption, in this work the Quaternion Fourier Transform is applied. The Fourier transform based Quaternion rotation improves the performance in both security and computation. The proposed system is implemented using the working platform of MATLAB, and the performance is compared with the conventional quaternion technique. The proposed system provided better performance based on the comparative analysis with respect to correlation coefficient, avalanche effect, computational speed, normalized correlation and histogram.