Visual Cryptography Based on an Interferometric Encryption Technique
Sang-Su Lee Lee, Jung-Chan Na Na, Sungwon Sohn, Cheehang Park Park, Dong-Hoan Seo, Soo-Joong Kim Kim · ETRI Journal · 2002
This paper presents a new method for a visual cryptography scheme that uses phase masks and an interferometer. To encrypt a binary image, we divided it into an arbitrary number of slides and encrypted them using an XOR process with a random key or keys. The phase mask for each encrypted image was fabricated under the proposed phase-assignment rule. For decryption, phase masks were placed on any path of the Mach-Zehnder interferometer. Through optical experiments, we confirmed that a secret binary image that was sliced could be recovered by the proposed method.