Patent ID: 8593259

Claim:
A method for authenticating a radiofrequency identification tag by a radiofrequency identification reader, the tag having an identifier accessible to the reader via a database of tag identifiers, comprising: sending of an authentication request by the reader to the tag; sending by the tag of a response, calculated by applying a first function to at least the identifier; calculating, by the tag and by the reader, a new identifier, by applying a second function to the identifier; if the response sent by the tag corresponds to a result obtained by applying said first function to an identifier in the database, sending by the reader of a first value, calculated by applying a third function to said identifier from the database; if the first value sent corresponds to a value obtained by applying the third function to the tag identifier, replacing in the tag the identifier with the new identifier calculated by the tag; sending of a second value to the reader, obtained by applying a fourth function to the new identifier calculated by the tag, if the second value sent corresponds to a value obtained by applying the fourth function to the new identifier calculated by the reader, replacing, in the database, the tag identifier with the new identifier.