Chang-Mok SHIN^* and Soo-Joong KIM

School of Electrical Engineering and Computer Science, Kyungpook National University, 1370 Sangyuk-Dong, Buk-Gu, Daegu 702-701, Republic of Korea

(Received August 15, 2005; Accepted January 18, 2006)

A phase-only encryption scheme using phase-encoded exclusive-OR (XOR) rules in a Fourier plane and a single path decryption system are presented. To generate phase-only encrypted data, a zero-padded original image, multiplied by a random phase image, is Fourier transformed and its real-valued data is encrypted with key data by using phase-encoded XOR rules. Since the original information is encrypted on the Fourier plane, the proposed encryption is more tolerant to loss of key information by scratching or cutting than previous XOR encryption in a space domain. A decryption is simply performed based on 2- f setup with spatial filter by Fourier transform for multiplication phase-only encrypted data with phase-only key data. Due to single path architecture without a reference wave, the proposed system is resistant to mechanical vibrations and fluctuation. Numerical simulations have confirmed the validity of the proposed encryption scheme and simple decryption architecture.

Key words: optical security system, Fourier transform, random phase encoding

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