Patent ID: 7856554

Claim:
A method of authenticating an object, the object having encoded thereon a plurality of data tags, each data tag encoding an object identifier for uniquely identifying the object, and a fragment of a digital signature of at least the object identifier, the digital signature comprising a plurality of fragments, said method comprising the steps of: reading the object identifier and the fragment encoded in one of the tags using a data reader; determining by the data reader a fragment identifier which identifies the fragment read by the reader; sending an authentication request from the data reader to a computer system, said authentication request comprising the object identifier, the fragment and the fragment identifier; receiving in the computer system the object identifier, the fragment and the fragment identifier; determining in the computer system a determined digital signature by calculating a digital signature of at least the object identifier; determining in the computer system a determined fragment from the determined digital signature using the fragment identifier; authenticating the object in the computer system by comparing the determined fragment with the fragment received from the reader; sending an authentication message from the computer system to the reader; receiving, in the data reader, the authentication message from the computer system, said authentication message comprising an indication of authenticity, a description of an object associated with the object identity and a digital signature of the authentication message; verifying the authentication message using the digital signature of the authentication message; and conveying the description of the object to a user if the authentication message is valid.