Improved algorithm for image encryption based on stochastic geometric moire and its application

A technique based on optical operations on moire patterns patterns for image encryption and decryption is developed. In this method, an image is encrypted by a stochastic geometric moire pattern deformed according to the image reflectance map. The decryption is performed using pixel correlation algorithm in the encrypted image and the stochastic geometrical moire pattern. The proposed technique has a number of advantages over existing encryption techniques based on moire gratings. No original moire grating can be reconstructed only from the encrypted image. Stochastic moire grating can be deformed in any direction what is an important factor of encryption security. Finally, the quality of the decrypted image is much better compared to decryption methods based on the superposition of the regular and deformed moire gratings. The proposed technique has a great potential, because the process is performed using computational algorithms based on optical operations and optical components are avoided. (c) 2007 Elsevier B.V. All rights reserved.