We define three privacy-preserving solutions to the problem of distributing secrets between manufacturers and vendors of items labeled with Electronic Product Code (EPC) Gen2 tags. The solutions rely on the use of an anonymous threshold secret sharing scheme that allows the exchange of blinded information between readers and tags. Moreover, our secret sharing scheme allows self-renewal of shares with secret preservation between asynchronous shareholders. The first two solutions address the eavesdropping and rogue scanning threats. The third solution mitigates as well tracking threats.