Abstract
In this paper, we propose an encryption method, in which a multi reference pattern is used in coaxial holographic data storage. The signal data patterns are multiplexed at one spot with multi reference patterns, which are the key code for secure readout. This method is easy to implement in coaxial holographic storage drives, and provides higher security against unauthorized readout and copying of the hologram disk. We experimentally demonstrate the encryption and decryption process with the proper and improper keys. Next, we analyze the degree of security provided by this method, and demonstrate a method of increasing the security further by recording more than 10 holograms at one spot. Finally, we record multiplexed holograms to reach 50 and 100 Gbit/in.2 with this encryption method, and analyze the degradation of the error rate.