ACOUSTICAL PHYSICALLY UNCLONABLE FUNCTION (PUF) AND SYSTEM

The present invention is a diverse acoustical object containing a range of particles that have acoustical wave impedances that are substantially different from the binder. The particles create a substantially different reflection as an acoustic wave is scattered by the particles. A negative reflection is created when the scattered wave is from a particle that has a wave impedance that is substantially less than the binder impedance. Practically, it may be necessary to encase this material in a thin material that will withstand the fabrication process (e.g., air or silicone elastomer could be encased in glass). If the wavelength is large compared to the encasing material thickness, then the reflection will be more dependent on the interior material. A mixture of materials that generate positive as well as negative reflections within the binder would add to the complexity of the PUF.