Hybrid Method of Document Image Encryption using ECC and Multiple Chaotic Maps

Abstract

Document imaging is one of the most important technology used to preserve, retrieve and to transmit old documents over the internet. Since open network threatens the security of such documents from being intercepted, the proposed scheme intends to provide enhanced security for such documents. The proposed hybrid algorithm includes Elliptic Curve Cryptography (ECC), and mixed chaotic system. The ECC encrypts the plain image based on the elliptic points generated by selecting a prime number. The mixed chaotic map includes two-dimensional logistic map and three-dimensional Lorenz map. The 2D logistic map is used for confusing the ECC encrypted image and 3D Lorenz map is used for diffusing the confused image. The two levels of confusion, first with byte level and second with bit level are introduced. The two levels of diffusion, first level with Lorenz map and second level with Fibonacci sequences are introduced. Better net pixel change rate and unified average change intensity with flat histogram and low correlation are achieved in this method. The key Sensitivity, Entropy, Mean Square Error, and Peak Signal to Noise Ratio analysis reveal that the proposed method is resistant to any external invasion. The encryption and decryption speed is increased by using programming techniques. The robustness of the algorithm is also checked and found to be robust against noise and loss of information.