Novel Image Encryption Algorithm Based on Hash Function

In this paper, a novel algorithm for image encryption based on SHA-512 is proposed. The main idea of the algorithm is to use one half of image data for encryption of the other half of the image reciprocally. Distinct characteristics of the algorithm are high security, high sensitivity and high speed that can be applied for encryption of gray-level and color images. The algorithm consists of two main sections: The rst does preprocessing operation to shufe one half of image. The second uses hash function to generate a random number mask. The mask is then XORed with the other part of the image which is going to be encrypted. The aim of this work is to increase the image entropy. Both security and performance aspects of the proposed algorithm are analyzed and satisfactory results are achieved in various rounds.