Method and device for marking objects and materials

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.