Coded data for disposal on or in a surface that includes a number of coded data portions. Each coded data portion encodes an identity of an object or the like associated with the surface. In addition, each coded data portion encodes at least part of a signature that is a digital signature of at least part of the identity and at least part of predetermined padding. This allows the coded data to be used to both identify and authenticate the object.
CROSS REFERENCES TO RELATED APPLICATION
The present application is a continuation of U.S. application Ser. No. 11/041,580 filed on Jan. 25, 2005, the entire contents of which are herein incorporated by reference.
