Securing multiple-single-channel color image using unequal spectrum decomposition and 2D-SLIM biometric keys

A novel multiple-single-channel color image cryptosystem based on unequal spectrum decomposition (USD) and 2D sine improved 1ogistic iterative chaotic map with infinite collapse modulation map (2D-SLIM) is proposed. In this method, R, G, and B channels of each color image of an authorized user is fused with corresponding LL sub-band of a gray-scale carrier image by inverse discrete wavelet transform (DWT) to obtain single-channel and watermarked image. The individual biometric key of an authorized user is produced by his/her phase encoded irisprint and then modulated by chaotic random phase mask (CRPM). So the parameters of CRPM are used as decryption keys with the uniqueness of the irisprint. The watermarked image as input image is normalized, multiplied with biometric key, and then Fresnel transformed. The Fresnel spectrum is divided into two complex-value masks by using unequal spectrum decomposition in which one phase mask is exploited as decryption key and other as ciphertext. The final ciphertext is obtained by adding individual ciphertexts. The encryption and decryption process can be realized with a hybrid optoelectronic system. Numerical simulations have been performed to verify the validity and feasibility of the proposed system.