Visual Cryptography based on Optical Interference

광학적 간섭현상을 이용한 시각 암호화 기법

In this paper, we proposed a new visual cryptography scheme based on optical interference which improves the contrast and SNR of reconstructed images comparing with conventional visual cryptography method. We divided an binary image to be encrypted into n slides. To encrypt them, (n-1) random independent keys and one another random key by XOR process between four random keys were prepared. XOR between each divided image and each random key makes encrypted n encrypted images. From these images, encrypted binary phase masks can be made. For decryption all of phase masks should be placed together in the interferometer such as Mach-Zehnder interferometer.