Experimental analysis of a joint free space cryptosystem

In this paper, we analyze a joint free space cryptosystem scheme implemented in an actual laboratory environment. In this encrypting architecture, the object to be encoded and the security key are placed side by side in the input plane without optical elements between the input and the output planes. In order to get the encrypted information, the joint Fresnel power distribution JFPD coming from the input plane is registered in a CMOS camera. The information of the encrypting key is registered with an off axis Fresnel holographic setup. The data registered with the experimental setup is digitally filtered to obtain the encrypted object and the encryption key. In addition, we explore the performance of the experimental system as a function of the object-camera and key-camera distances, which are two new parameters of interest. These parameters become available as a result of developing this encrypting scheme. The theoretical and experimental analysis shows the validity and applicability of the cryptosystem.