In this paper we propose a new (to our knowledge) complex spatial modulation method to encode data pages applicable in double random phase encryption (DRPE) to make the system more resistant to brute-force attack. The proposed modulation method uses data page pixels with random phase and amplitude values with the condition that the intensity of the interference of light from two adjacent pixels should correspond to the encoded information. A differential phase contrast technique is applied to recover the data page at the output of the system. We show that the proposed modulation method can enhance the robustness of the DRPE technique using point spread function analysis. Key space expansion is determined by numeric model calculations.
© 2012 Optical Society of America
Optics in Computing
Original Manuscript: July 31, 2012
Revised Manuscript: October 9, 2012
Manuscript Accepted: November 5, 2012
Published: November 27, 2012
Tamás Sarkadi and Pál Koppa, "Optical encryption using pseudorandom complex spatial modulation," Appl. Opt. 51, 8068-8073 (2012)