1. A method for use in combination with a digital object comprising at least one sub-object, said method providing a digital signature for at least one region, where each of said at least one region is comprised of all or part of one of said at least one sub-object, and where said sub-objects may be rearranged within the object without invalidating the digital signature, the method comprising: creating an array comprising, for each of said at least one region, a region specifier identifying the region; producing a digital signature based on data comprising each region and said array; and adding a signature sub-object comprising said array and said digital signature to the digital object.