A secure image encryption algorithm based on fractional transforms and scrambling in combination with multimodal biometric keys

In today’s digital world, security is a preeminent element in the transmission of digital images. In this paper, image encryption algorithm is proposed using fractional transform and scrambling along with multimodal biometric keys. For unauthorized persons, it is very difficult to retrieve the biometric keys. Firstly, both iris and fingerprint binary codes are XORed and given to the original image. This randomized image is secured using fractional order as a key. The significant feature of fractional transforms benefits from its extra degree of freedom that is provided by its fractional orders. The fractional order is calculated from the iris key. To make the encryption more confusing, scrambling is used to shuffle the position of pixels. Experimental results like histogram analysis, correlation analysis, peak signal-to-noise ratio, mean square error, structural similarity index measure, spectral distortion, information entropy, key sensitivity analysis, differential attacks and spoofing attacks verify the efficacy of proposed algorithm.