Multilayered structures and uses thereof in security markings

A method of producing a plurality of security markings, the method comprising:

• multilayer coextruding one or more polymer materials to form disordered and/or non-uniform polymer layers and multiplying the disordered and/or non-uniform polymer layers to form a film that has a randomness defined by disorder and/or non-uniformity within the film that result from the multilayer coextrusion and multiplying processes, wherein the film includes a plurality of regions and wherein each region has an electromagnetic transmission and/or reflection spectrum and/or spectra upon receipt of electromagnetic radiation within a photonic bandgap region of the film that is unique to the region of the film.