Initial tamper tests of novel tamper-indicating optical physical unclonable functions.

Optical physical unclonable functions (O-PUFs) are materials containing a large number of randomly distributed degrees of freedom that can be probed optically. We develop tamper-indicating O-PUF seals using polyurethane adhesives with dispersed nanoparticles, where authentication is performed by use of wavefront-shaping controlled reflection. We test the material's and authentication method's tamper-indicating ability using tampering attacks including: mechanical, thermal, and chemical attacks, with the results demonstrating the material/method's robust tamper-indicating ability. Additionally, we demonstrate that authentication depends strongly on the microscopic distribution of nanoparticles within the polymer, which is unfeasibly difficult to clone. These results are the first demonstration of the validity of this technique for use as tamper-indicating seals.