Abstract: Shippers can provide shipment data that may be inaccurate. A third party verifier can independently verify the physical attributes of a shipment and can append digital verification information to the forms used by the sender and recipient to exchange physical attribute data. A validation key added by the third party verifier can comprise a check digit which can, in combination with a published algorithm, be used to verify the associated physical attribute data. The validation key can also comprise another check digit which can, in combination with a private algorithm known only by the third party verifier, be used to further verify the associated physical attribute data.