Techniques are disclosed for writing data directly onto a product to record each ownership transfer. As a result, the product itself now carries a traceable, auditable, non-forgeable, non-repudiable proof of ownership (and, optionally, ownership history) that can be used in a variety of ways. This recorded ownership transfer information provides an electronic receipt, which may be used by the present owner to prove his or her ownership. (Optionally, other types of transfers may be recorded in addition to, or instead of, ownership transfers.) A transfer agent or registrar creates a unique transaction identifier to represent the transfer, and preferably creates a cryptographic signature over fields representing the transfer. This information is then recorded in a repository that is external from the product.