Moving Target Defense (MTD) is a proactive security strategy designed to enhance cyber-resilience by dynamically altering system parameters, thereby preventing adversaries from acquiring the critical information needed to execute stealth attacks. In this paper, we consider the case in which the operator modifies the admittance of branches to enable MTD, and focus on the problem of effectively protecting the system with fewer number of branch admittance modifications and shorter computational time. Specifically, we identify the ineffectual branches whose admittance modification do not contribute to the improvement of MTD effectiveness via theoretical analysis. Building on these insights, we propose the Bus Traversal-based MTD (BT-MTD), which is a bus-oriented algorithm that traverses over the buses of the network according to analytically derived guidelines. The performance of the BT-MTD is evaluated and compared with four existing strategies on standard IEEE test systems, demonstrating its robustness and superior performance in effectiveness, efficiency, and computational cost. The code of BT-MTD is available at: https://github.com/YJY101/BT-MTD.

翻译：摘要：移动目标防御（MTD）是一种主动安全策略，通过动态改变系统参数以增强网络弹性，从而阻止攻击者获取执行隐蔽攻击所需的关键信息。本文考虑运营商通过修改支路导纳实现MTD的场景，重点研究如何以更少的支路导纳修改次数和更短的计算时间有效保护系统。具体而言，通过理论分析识别出导纳修改无助于提升MTD效果的无效支路。基于这些发现，我们提出基于母线遍历的MTD（BT-MTD），这是一种面向母线的算法，根据分析推导的准则遍历网络中的母线。在标准IEEE测试系统上评估BT-MTD的性能，并与四种现有策略进行对比，结果表明其在有效性、效率和计算成本方面均展现出鲁棒性和优越性能。BT-MTD代码已开源：https://github.com/YJY101/BT-MTD。