基于椭圆曲线密码学的 QKD 经典信道高效认证协议

An Efficient Authentication Protocol for QKD Classical Channels Based on Elliptic Curve Cryptography

摘要: 量子密钥分发 (QKD) 技术依赖于一个公开的经典信道进行后处理协商，但协议本身不提供信道认证，使其极易遭受中间人攻击，这是 QKD 在关键基础设施中实用化部署的核心障碍。鉴于此，本文选用并优化了一种高效认证协议，旨在为 QKD 的经典信道提供初始认证。该协议基于椭圆曲线密码学 (ECC) 的 MTI/A0 方案，通过预置的长期密钥和会话中交换的临时密钥实现隐式认证。我们使用形式化的安全模型和非形式化的分析对协议进行了全面的安全评估。结果表明，该协议能够有效抵御中间人攻击、重放攻击和密钥泄露伪装攻击，并具备弱前向安全性。性能分析表明，该协议在计算开销 (每方 3 次标量乘法) 和通信开销 (66 字节) 方面具有显著优势，在安全性和性能之间取得了理想的平衡点，完全适用于电力系统等对低延迟有严苛要求的关键基础设施。

Abstract: Quantum Key Distribution (QKD) technology relies on a public classical channel for post-processing negotiation, yet the protocol itself does not provide channel authen- tication, making it highly vulnerable to Man-in-the-Middle (MitM) attacks. This vulnerability is a core obstacle to the practical deployment of QKD in critical in- frastructures. In view of this, we select and apply a new efficient authentication protocol to provide initial authentication for the QKD classical channel. The protocol is based on the MTI/A0 scheme using Elliptic Curve Cryptography (ECC), achieving implicit authentication through pre-deployed long-term keys and session-ephemeral keys. We conducted a comprehensive security evaluation of the protocol using formal security models and non-formal analysis. The results show that our protocol effective- ly resists MitM, replay, and key-compromise impersonation attacks, while providing weak forward secrecy. Performance analysis indicates that the protocol has significan- t advantages in terms of computational cost (3 scalar multiplications per party) and communication cost (66 bytes), striking an ideal balance between security and per- formance. It is fully applicable to critical infrastructures with stringent low-latency requirements, such as power grid systems.