  Encryption techniques demonstrate a great deal of security when implemented
in an optical system (such as holography) due to the inherent physical
properties of light and the precision it demands. However, such systems have
shown to be vulnerable during digital implementations under various
crypt-analysis attacks. One of the primary reasons for this is the predictable
nature of the security keys (i.e., simulated random keys) used in the
encryption process. To alleviate, in this work, we are presenting a Physically
Unclonable Functions (PUFs) for producing a robust security key for digital
encryption systems. To note, a correlation function of the scattered perfect
optical vortex (POV) beams is utilized to generate the encryption keys. To the
best of our knowledge, this is the first report on properly utilizing the
scattered POV in optical encryption system. To validate the generated key, one
of the standard optical encryption systems i.e., Double Random Phase Encoding,
is opted. Experimental and simulation results validate that the proposed key
generation method is an effective alternative to the digital keys.
