An authentication method consisting in establishing a description, also referred to as subsequent, of an authentication device comprising an encoded set which in turn comprises disrupting elements (111, 112 et seq.) which disrupt light, and in comparing this description with a description, also referred to as original, of said authentication device for measuring the difference between said descriptions, characterized in that: - said disrupting elements (111, 112 et seq.) are grouped in sub-assemblies (1A, 1B et seq.) also referred to as modules, with a module returning light in substantially different ways depending on the view point from which it is observed, - a description comprises one operation, hereinafter referred to as an acquisition, which consists in measuring, using measuring means, the brightness of a plurality of said modules (1A, 1B et seq.), in one or more wavelengths or different wavelengths sets, - said original description is established from an acquisition from a view point, also referred to as original, defined by reference to said authentication device, - and in that the procedure making it possible to establish said subsequent description and to make said comparison comprises: - determining -using said positioning means interacting with a recognizable graphical structure, also referred to as the marker - the three-dimensional position where said acquisition means is located with reference to said authentication device, - an acquisition made when said acquisition means is positioned close to the original view point, - and at least one additional acquisition made: - either from a view point substantially different from the original view point, - or in a light different from the one used for the acquisition which made it possible to establish said original description. - said disrupting elements (111, 112 et seq.) are grouped in sub-assemblies (1A, 1B et seq.) also referred to as modules, with a module returning light in substantially different ways depending on the view point from which it is observed, - a description comprises one operation, hereinafter referred to as an acquisition, which consists in measuring, using measuring means, the brightness of a plurality of said modules (1A, 1B et seq.), in one or more wavelengths or different wavelengths sets, - said original description is established from an acquisition from a view point, also referred to as original, defined by reference to said authentication device, - and in that the procedure making it possible to establish said subsequent description and to make said comparison comprises: - determining -using said positioning means interacting with a recognizable graphical structure, also referred to as the marker - the three-dimensional position where said acquisition means is located with reference to said authentication device, - an acquisition made when said acquisition means is positioned close to the original view point, - and at least one additional acquisition made: - either from a view point substantially different from the original view point, - or in a light different from the one used for the acquisition which made it possible to establish said original description.