Patent ID: 8463712

Claim:
A traceability system for using a certificate issued by a certificate authority device to trace a supply chain by a signature chain, the traceability system comprising at least one computer processor adapted to implement: a signature chain for the supply chain issued by the certificate authority device, wherein in the supply chain a deliverer receives a supply of parts for products from disclosed suppliers and undisclosed private suppliers to at a delivery destination, the deliverer ships the products comprising the parts to at least one third party, the disclosed suppliers being identified to the third party and the undisclosed private suppliers being unidentified to the third party, the signature chain comprising: a first signature based on a first individual certificate issued to a disclosed supplier device selected from the disclosed suppliers; at least one second signature based on a group certificate issued by the certificate authority device, the group certificate being common to a plurality of the undisclosed private suppliers; and a third signature based on a second individual certificate of a supplier manager after said signature chain is signed by the at least one second signature; a verifier device configured to verify said signature chain while maintaining confidentiality of said private suppliers, wherein the verifying is based on a group public key received from said certificate authority device.