A method of authenticating an object comprising an identifier is provided. The method comprises the steps of: (i) reading the identifier using a data reader to generate identity data; (ii) sending an authentication request from the data reader to a computer system, the request comprising the identity data; (iii) receiving, in the data reader, an authentication message from the computer system, the authentication message comprising an indication of authenticity, a description of an object associated with the identity data and a digital signature of the authentication message; (iv) verifying the digital signature; and (v) conveying the description of the object to a user if the signature is valid.