Abstract: A method of generating at least one digital signature for at least one surface of a material element, referred to as an “examined surface.” The method is performed by a data processor system, and may include, for each examined surface: obtaining an “offset” image having at least a portion showing the examined surface; obtaining at least one zone of interest in the offset image by putting into correspondence the offset image with at least one predetermined “equivalent” zone that is included in a model image having at least a portion representing a “reference” surface; obtaining a “registered” image by registering the offset image with the model image by applying a homography transformation to the offset image, wherein the transformation is obtained from the at least one zone of interest and the at least one equivalent zone; and generating the digital signature, which characterizes the structure of the examined surface, from the registered image.

Abstract: A method of producing an authenticatable article. An overt feature is produced in the article using a fabricating technique which is selected based on a material of the article so as to produce the overt feature having predetermined, reproducible macroscopic characteristics as well as random, non-reproducible microscopic characteristics rendering the article physically unique. The overt feature including the microscopic characteristics are imageable using a predetermined imaging technology to produce an overt feature image. An authentication signature is generated based on the overt feature image and stored in a central database. The overt feature may alternatively be produced in an apparatus or means used to manufacture authenticatable articles such that the overt feature including the random, microscopic characteristics is reproduced in the articles. The overt feature and generated authentication code therefore corresponds to articles manufactured using that apparatus or means.