[OPTICAL REVIEW Vol. 10, No. 1 (2003) 4-7]
© 2003 The Optical Society of Japan

Optical Security System using Phase-based Virtual Image and Interferometer

Dong-Hoan SEO* and Soo-Joong KIM

School of Electrical Engineering and Computer Science, Kyungpook National University, Daegu 702-701, Korea

(Received September 13, 2002; Accepted October 30, 2002)

An improved optical security system is proposed based on three phase-encoded images and the principle of interference. This optical system consists of one phase-encoded virtual image to be encrypted and two phase-encoded images, encrypting image and decrypting key. The proposed encryption is performed by the multiplication of an encrypting image and a phase-encoded virtual image which does not contain any information from the decrypted (original) image. Therefore, even if an unauthorized user steals and analyzes the encrypted image, he cannot reconstruct the required image. This virtual image protects the original image from counterfeiting and unauthorized access. Optical experiments show the proposed method is a very useful optical security system.

Key words: optical security system, optical encryption, random phase, phase mask




© Japan Society of Applied Physics