基于SM2/SM3的智能电表身份认证协议

An Identity Authentication Protocol for Smart Meters Based on SM2/SM3

摘要: 针对智能电网高级计量基础设施中智能电表面临的身份伪造、数据窃听与篡改等安全威胁，以及现有认证方案在计算开销、密钥管理、会话密钥独立与国密算法体系化应用等方面的不足，本文提出了一种基于SM2与SM3的双阶段混合身份认证协议。该协议采用“分层–混合”密码架构，将高开销的SM2椭圆曲线公钥运算限制于设备初始注册阶段，用于实现强安全的双向身份认证与长期主密钥协商；在日常高频通信阶段，则完全基于SM3-HMAC与SM4对称加密实现轻量级重认证与会话密钥动态派生，达到长期密钥仅用于认证、短期密钥专用于加密的密钥分离与纵深防御效果。协议无需实时在线可信第三方，规避了单点故障与性能瓶颈。通过仿真环境下的功能测试、性能测试及安全攻击测试，结果表明：日常会话阶段电表侧计算耗时仅3.39 ms，较第一阶段降低约65%，通信开销仅169 Byte；协议能够有效抵抗假冒、重放及篡改攻击，并满足会话密钥独立性。形式化分析(ProVerif)进一步验证了协议的机密性与双向认证属性。与现有代表性方案相比，本协议在实现国密算法(SM2/SM3/SM4)体系化合规应用的同时，在安全性与计算/通信效率之间取得了更优平衡，为智能电网的自主可控安全建设提供了可行的技术参考。

Abstract: In response to the security threats such as identity forgery, data eavesdropping and tampering faced by smart meters in the advanced metering infrastructure of smart grids, as well as the deficiencies of existing authentication schemes in terms of computational overhead, key management, forward secrecy and systematic application of national cryptographic algorithms, this paper proposes a two-stage hybrid identity authentication protocol based on SM2 and SM3. This protocol adopts a “layered-hybrid” cryptographic architecture, restricting the high-overhead SM2 elliptic curve public key operation to the initial device registration stage to achieve strong two-way identity authentication and long-term master key negotiation; in the daily high-frequency communication stage, it is completely based on SM3-HMAC and SM4 symmetric encryption to achieve lightweight re-authentication and dynamic derivation of session keys, achieving the effect of key separation and depth defense where long-term keys are only used for authentication and short-term keys are exclusively used for encryption. The protocol does not require a real-time online trusted third party, avoiding single point of failure and performance bottlenecks. Through functional tests, performance tests and security attack tests in a simulation environment, the results show that the calculation time on the meter side in the daily communication stage is only 3.39 ms, about 65% lower than the first stage, and the communication overhead is only 169 bytes; the protocol can effectively resist spoofing, replay and tampering attacks, and meet forward secrecy. Formal analysis (ProVerif) further verifies the confidentiality and two-way authentication properties of the protocol. Compared with existing representative schemes, this protocol achieves a better balance between security and computational/communication efficiency while realizing the systematic compliance application of national cryptographic algorithms (SM2/SM3/SM4), providing a feasible technical reference for the autonomous and controllable security construction of smart grids.