Information Hiding of Two-dimensional Code by Multi-layer Optical

Optical information media printed on paper use printing materials to absorb visible light. There is a two-dimensional code, which may be encrypted but also can possibly be copied. Hence, we envisage an information medium that cannot possibly be copied and thereby offers high security. At the surface, the normal two-dimensional code is printed. The inner layers consist of two-dimensional codes printed using a variety of materials, which absorb certain distinct wavelengths, to form a multilayered two-dimensional code. Information can be distributed among the two-dimensional codes forming the inner layers of the multiplex.