Under surface marking process for a public/private key

A method of placing a three dimensional, unique, pre calculated diffractive mark below (sub surface) a desired transparent or reflective substrate using laser ablation, such that upon appropriate interrogation using a point source of light, through the mark, the original image is made visible;

A method of placing a three dimensional, unique, pre calculated diffractive mark below (sub surface) a desired transparent or reflective substrate using a Digital Micromirror Device (DMD) type reflective surface in conjunction with a grid of convex lenses (lenselets) that focus several laser beams simultaneously and ablate the desired substrate such as a transparent or reflective surface such that upon interrogation with an appropriate point source of light, through the mark, the original image is made visible;

A method of placing a three dimensional, unique, pre calculated diffractive mark below (sub surface) a desired transparent or reflective substrate comprising of providing a substrate for supporting recorded image information in a binary form;

• providing a first binary pattern containing partial information of a first original image;
• providing a second binary pattern containing the remaining (complementary) information of a second original image, said first and a second binary patterns arranged as marks on said substrates in two different locations, in a desired manner to thereby create a recording of an integrated image including said first and second original images, such that upon interrogation with an appropriate point source of light, through the mark, the original image is made visible, and