A public and private key image encryption by modified approach of Vigener cipher and the chaotic maps

Abstract

ABSTRACT The article presents a real-time image encryption using a modified approach of Vigenère cipher and the chaotic maps with an efficient key management. The modification is provided to Vigenère cipher through the key expansion procedure. The proposed encryption chooses four random keys of 8-tuples to expand into the initial key block. Thereafter, the Vigenère cipher encrypts the pixels blocks using the initial key block and the next blocks through key updation using the XOR operation and the Arnold transform. Later, the partially encrypted image is further scrambled through the Baker map to increase the randomness and unpredictability of the data. The chosen secret key parameters are exchanged publicly through the Diffie–Hellman key exchange agreement. Simulation results and comparison analysis of some extant systems ensure that the proposed algorithm is secure against cryptanalytic attacks and efficient in real-time image processing. Further, the average execution time for encryption and decryption of an image with size is 0.4926 which is very efficient than a typical and recent encryption scheme.