A method of authenticating an object, the method including: sensing coded data provided on or in a surface associated with the object; determining, from the sensed coded data: an identity of the object; a plurality of signature fragments, the signature being a digital signature of at least part of the identity; determining, using the plurality of signature fragments, a determined signature; generating, using the determined signature and a key, a generated identity; comparing the identity to the generated identity; and, authenticating the object using the results of the comparison.