Analysis of Chaotic Image Encryption based on DPFrFT and Biokeys

A new biometric inspired chaotic image encryption technique is proposed. The idea behind the proposed technique is to capture the biometric image of the sender and then the image is pre-processed to estimate the initial seed of nonlinear chaotic map and feature vector. This feature vector is used to obtain the biometrically encoded bit stream. The original image is randomized using the random matrix generated by the iteration of Nonlinear Chaotic Map. Then the randomized image is encrypted using Dual Parameter Fractional Fourier Transform, Hessenberg Decomposition and the feature vector to get the randomized encrypted image. Then inverse Dual Parameter Fractional Fourier Transform is performed on the randomized encrypted image to get the encrypted image. The encrypted image can be decrypted by using the reverse process of encryption. To analyse the randomness of different chaotic maps, the above described method can be carried out using 1D, 2D and 3D chaotic maps and a comparative study on them is conducted. Theoretical analysis and computer simulations have shown that the proposed technique is efficient and secure.