A method for assigning identifiers (Idij) to objects (Oij), and for discriminating said objects (Oij) from the identifiers assigned, said objects (Oij) being comprised of a set of objects including at least two categories of objects, with at least one first category of so-called sensitive objects (Ois), and at least one second category of so-called common objects (Oic), characterised in that the method includes in particular the different steps of: - assigning an identifier (Idij) to each object of a plurality of objects of the set of objects by performing the following operations: - for each sensitive object (Ois), performing an operation of calculating a signature by means of a determined signature function involving a signature key (Kp), at least one public parameter associated with the sensitive object considered (Ois), and then assigning as an identifier an identification number including at least the signature calculated, the identifier of the sensitive object being thus an identifier signed; - for each common object (Oic), assigning as an identifier an identification number distinct from the identifiers of the other common objects without performing the operation of calculating the signature performed for each sensitive object, the identifier of the common object being an identifier the value of which is a result value of the determined signature function used for assigning the identifiers to the sensitive objects, the identifier being unsigned by the determined signature function; - transmitting the identifier of the object to a discrimination piece of equipment, having a key (Kp') for checking each signature calculated for the sensitive objects, said discrimination piece of equipment being able to discriminate the identifiers assigned to each object of the plurality of objects to comprise at least a first group of objects and a second group of objects which are distinct. - assigning an identifier (Idij) to each object of a plurality of objects of the set of objects by performing the following operations: - for each sensitive object (Ois), performing an operation of calculating a signature by means of a determined signature function involving a signature key (Kp), at least one public parameter associated with the sensitive object considered (Ois), and then assigning as an identifier an identification number including at least the signature calculated, the identifier of the sensitive object being thus an identifier signed; - for each common object (Oic), assigning as an identifier an identification number distinct from the identifiers of the other common objects without performing the operation of calculating the signature performed for each sensitive object, the identifier of the common object being an identifier the value of which is a result value of the determined signature function used for assigning the identifiers to the sensitive objects, the identifier being unsigned by the determined signature function; - for each sensitive object (Ois), performing an operation of calculating a signature by means of a determined signature function involving a signature key (Kp), at least one public parameter associated with the sensitive object considered (Ois), and then assigning as an identifier an identification number including at least the signature calculated, the identifier of the sensitive object being thus an identifier signed; - for each common object (Oic), assigning as an identifier an identification number distinct from the identifiers of the other common objects without performing the operation of calculating the signature performed for each sensitive object, the identifier of the common object being an identifier the value of which is a result value of the determined signature function used for assigning the identifiers to the sensitive objects, the identifier being unsigned by the determined signature function; - transmitting the identifier of the object to a discrimination piece of equipment, having a key (Kp') for checking each signature calculated for the sensitive objects, said discrimination piece of equipment being able to discriminate the identifiers assigned to each object of the plurality of objects to comprise at least a first group of objects and a second group of objects which are distinct.