Patent ID: 8432257

Claim:
A computer-implemented method of providing a product-integral transaction receipt, comprising: computing, for each ownership transfer of the product, a cryptographic signature over fields describing the transfer, the fields comprising at least a non-changeable globally-unique identifier computed to represent the transfer; for each ownership transfer of the product, permanently recording the cryptographic signature and at least a portion of the fields describing the transfer on the product in a memory of a product-integral device as a transaction receipt for the transfer, the portion comprising at least the non-changeable globally-unique identifier, wherein the permanently recording comprises appending the non-changeable globally-unique identifier to a product-integral transfer record stored in the memory, the product-integral transfer record representing, for each prior transfer of the product, a corresponding transaction receipt; and recording, for each ownership transfer of the product, a copy of the cryptographic signature and the fields as a transfer record in a separate repository, the transfer record being indexed in the separate repository by the non-changeable globally-unique identifier.