A system for enabling verification in traceability of a supply chain while maintaining confidentiality of private suppliers. A group signature is applied to an undisclosed supplier. The undisclosed supplier previously receives registration to the certificate authority device, and performs a group signature based on the certificate issued by the certificate authority device. A disclosed supplier and the undisclosed supplier sign and generate a signature chain when they ship parts. A verifier device receives a signature chain with products shipped from the supplier manager device, divides a signature of the disclosed supplier from a signature chain, and verifies the undisclosed supplier from the group signature. Identification of the undisclosed supplier is performed by a third-party auditor system requested to do so by the verifier device by using a group private key.