Double Encryption Algorithm for Massive Personal Biometric Authentication Images Based on Chaotic Mapping for Future Smart Cities

Abstract

Abstract To address the problems of low encryption security, slow encryption speed, and small key space of personal biometric authentication image, a double encryption algorithm of image based on chaotic mapping is proposed. The global block-matching strategy of sparse clustering is used to remove the image noise, and the encrypted key information in the biometric authentication image is extracted by mathematical morphology. The logistic index is used to disrupt the image information distribution, bit scrambling is used to double scramble the image, and the Secure Hash Algorithm (SHA)-256 hash function is used to generate the initial value of the chaotic system to obtain the chaotic map and the random variable sequence of hyperchaotic Chen system, and the chaotic sequence is transformed into the ciphertext image matrix after exclusive OR (XOR) operation in order to realize the double encryption of personal biometric authentication image. The results show that the proposed method has large key space, high encryption accuracy, fast efficiency, and better security performance.