Multi-Image Encryption by Random Grids

A random grid is a 2-dimensional array. Each pixel in random grid is either transparent or dark. Darkness and transparency of each pixel are determined by a total random process. This paper introduces a new method for multi-image encryption by random grids. In the proposed method, three binary images are encrypted by only two random grids in such a way that each random grid does not give the attacker any information. Binary images can not be decrypted and reconstructed only when two random grids are accessible. Decryption process is done by XOR operation. The result of implementation of the proposed method showed that reconstructed images have higher visual quality in comparison with previous approaches.