Abstract: OpenID is a user-centered digital identity recognition framework and a decentralized online identity authentication system. It has the characteristics of openness, decentralization and freedom. However, some existing OpenID protocols still have many deficiencies in effectively protecting user privacy. For example, identity providers can learn the relying party information logged in by users through each use. In view of the above problems, a design idea of the OpenID protocol based on blind signature is proposed, which blinds the website identifier of the OpenID relying party. This paper first designs an identity-based blind signature scheme based on the national secret algorithm SM9, and proves that the security of this scheme depends on SM9 signature scheme. Then, based on the above blind signature scheme, an OpenID protocol is designed. Finally, the efficiency and security of the proposed OpenID protocol are demonstrated through simulation experiments and theoretical analysis.

Key words: OpenID protocol, SM9 algorithm, blind signature, security analysis