Abstract: A material marking method includes: generating a code; randomly selecting at least one area of the material; and marking by laser shot on the surface of, or inside the material in each the area of the material to represent the code there in a way that cannot be detected by the naked eye. Preferentially, the randomly selecting step is performed for each item of material to be marked. Preferentially, during the code generating step, a two-dimensional bar code is generated, and during the marking step, the two-dimensional bar code is represented. Preferably, the method includes marking the material in order to represent a mark visible to the naked eye, at least one part of a marking area of a mark visible to the naked eye is selected randomly and/or the visible mark bears an item of information representative of the position of at least one area where the code that cannot be detected by the naked eye is represented.

Abstract: A material marking method includes: generating a code; randomly selecting at least one area of the material; and marking by laser shot on the surface of, or inside the material in each the area of the material to represent the code there in a way that cannot be detected by the naked eye. Preferentially, the randomly selecting step is performed for each item of material to be marked. Preferentially, during the code generating step, a two-dimensional bar code is generated, and during the marking step, the two-dimensional bar code is represented. Preferably, the method includes marking the material in order to represent a mark visible to the naked eye, at least one part of a marking area of a mark visible to the naked eye is selected randomly and/or the visible mark bears an item of information representative of the position of at least one area where the code that cannot be detected by the naked eye is represented.