Patent ID: 7467301

Claim:
A method of authenticating an object using a processor, the method including steps of: receiving indicating data, the indicating data being generated in response to sensing of coded data provided on or in a surface associated with the object, the indicating data being indicative of: an identity; and, a part of a signature, the signature being a digital signature of at least a part of the identity and at least part of predetermined padding, and comprising a plurality of signature parts; determining from the indicating data, a received identity, a received signature part and a received signature part identifier; determining, using the received identity and the received signature part identifier, a determined signature part; comparing the determined signature part to the received signature part; and authenticating the object using the result of the comparison, wherein the step of determining the determined signature part comprises sub-steps of: determining, using the received identity, the predetermined padding; determining, using the predetermined padding, the received identity, and a secret key, the determined signature; and determining the determined signature part from the determined signature and the received signature part identifier.