[OPTICAL REVIEW Vol. 11, No. 1 (2004) 34-37]
© 2004 The Optical Society of Japan

Gray-Level Image Encryption Scheme Using Full Phase Encryption and Phase-Encoded Exclusive-OR Operations

Chang-Mok SHIN*, Dong-Hoan SEO and Soo-Joong KIM

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

(Received August 29, 2003; Accepted November 26, 2003)

A new gray-level image encryption scheme based on phase-encoded exclusive-OR (XOR) operations and a full phase-encoding method is presented. The gray-level image can be sliced into binary images which have the same pixel level, and each of them is encrypted by phase-encoded XOR operations with each phase-encoded binary random image. We combine XORed images and phase-encoded binary random images into an encrypted image and a key image, respectively. Gray-level encrypted data and key data are obtained by the phase-encoding process of the encrypted image and the key image in a space domain. The decryption process is simply implemented by using a phase-visualization system and the performance of the proposed scheme is evaluated by computer simulation.

Key words: optical security system, random phase encoding, optical correlators

*E-mail address: lensless@palgong.knu.ac.kr