Deterministic phase encoding encryption in arbitrary phase-step digital holography
Chi-Ching Chang, Wang-Ta Hsieh, Ming Kuei Kuo · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2010
A deterministic phase-encoded encryption system, which adopts a lenticular lens array (LLA) sheet as a phase modulator (key), based on arbitrary two-step phase-shift interferometry (PSI), with an unknown phase step, is presented. The principle of encryption and decryption which is using a LLA in arbitrary unknown two-step PSI is given. With the aid of key holograms (right key), it can be theoretically shown that only the reconstructed object wavefront term will be left in the image plane, and all the accompany undesired terms be eliminated. Thus the hidden information of object wavefront in this encryption system can be numerically and successfully decrypted using arbitrary unknown two-step PSI with right key. For comparisons, computer simulations are carried out to verify the principle of encryption and decryption without key, with wrong key and with right key, respectively.