Personalized authentication of products using terahertz waves

1 . A method for authenticating an article, comprising the following steps in an end-of-production phase of the article:

defining on the article a reference zone with a random internal texture resulting from a production process of a material of the article;

applying a visible marking directly on a surface of the article at a location corresponding to the reference zone, wherein the visible marking guides placement of a terahertz proximity imager during subsequent authentication;

acquiring a density image of a volume of material beneath the reference zone using a terahertz proximity imager positioned according to the visible marking;

generating a reference signature from the density image; and

recording the reference signature in an authentication system with a unique identifier associated with the article, wherein the authentication system is configured to:

receive a current density image of the article's reference zone acquired during a subsequent authentication phase; and

return the reference signature associated with the article using the unique identifier.

2 . The method according to claim 1 , comprising the following steps in a subsequent authentication phase of the article:

finding the reference zone on the article using the visible marking;

acquiring the current density image of the article's reference zone using a terahertz proximity imager;

receiving the reference signature associated with the article from the authentication system; and

searching for the reference signature in the current density image.

3 . The method according to claim 1 , wherein the imager comprises a pixel array larger than the reference zone.

4 . The method according to claim 3 , wherein the reference signature is a sub-image including a sequence of pixels aligned in the reference zone.

5 . The method according to claim 3 , wherein the reference signature is a sub-image including the reference zone.

6 . The method according to claim 4 , comprising the following step:

segmenting pixel values of the imager into a number of levels smaller than a bit resolution of a pixel.

7 . The method according to claim 6 , comprising the following step:

segmenting the pixel values into three levels.

8 . The method according to claim 1 , wherein the proximity terahertz imager is integrally implemented in CMOS technology.

9 . The method according to claim 8 , wherein the proximity terahertz imager is a lensless reflection imager.

10 . The method according to claim 8 , wherein the terahertz proximity imager is a near-field imager.

11 . The method according to claim 5 , comprising the following step:

segmenting pixel values of the imager into a number of levels smaller than a bit resolution of a pixel.

12 . The method according to claim 11 , comprising the following step:

segmenting the pixel values into three levels.