Abstract: Under the background of extensive interconnection of power terminals, the traditional security and stability control architecture gradually shifts to distributed Special Protection System(SPS) with terminal intelligent collaboration. However, the identity authentication mechanism between the security and stability control terminals of the smart grid is not yet complete, thus it has become an irresistible trend to establish the mutual authentication and trust mechanism between the security and stability control terminals so as to avoid power system from cyber attacks as far as possible. This paper first analyzes the current status of SPS and the security risks SPS faced due to lack of targeted identity authentication mechanisms. On this basis, the alliance blockchain and the appropriate consensus mechanism are selected, and an identity authentication scheme based on blockchain technology that meets the characteristics of SPS is proposed. The distributed identity authentication scheme of blockchain technology uses hash chains and a distributed storage scheme to achieve lightweight authentication. Finally, the efficiency and security of the scheme are analyzed. The identity authentication mechanism proposed in this paper meets the high requirements of the power system and can defend against several common network attacks such as man-in-the-middle attacks and DoS attacks, thus ensuring the safe and stable operation of the power system.

Key words: blockchain, power system, safety and stability control terminal, identity authentication, decentralized storage