TWC: Small: Communication under Adversarial Attacks in Complex Networks - Fundamental Limits and Secure Coding Strategies

当今世界高度依赖互联网、WiFi或蜂窝网络等通信系统的完整性。随着网络变得越来越普遍，它们越来越多地被用于通信和存储关键数据以及敏感数据，因此对可靠性和安全性提出了更严格的要求，即使在部分停电、自然灾害或最重要的对抗性攻击等极端情况下也必须保持可靠性和安全性。这项研究旨在了解保护复杂的实用网络免受对手攻击的基本限制，以及如何通过最佳安全策略实现这些限制，从而弥合高级理论研究和现实解决方案开发之间的差距。此外，该项目能够对采用可靠联网通信的许多其他关键应用程序提供显著的变革性影响，例如在医疗保健、环境监测、金融等领域。该项目还提供了一个平台，用于通过新建立的理论和实践、雄心勃勃的教育计划以及积极吸引来自未被充分代表的人口统计学的学生来创造更广泛的技术、社会、研究和教育影响，因为通过新建立的理论和实践、雄心勃勃的教育计划以及积极地吸引来自未被充分代表的人口统计学的学生。具体地说，该项目侧重于在真实网络系统中很重要的方面(例如，分布式用户、异质性、延迟要求、由概率分布描述的对手的行为)，但在当前文献中知之甚少，并试图阐明每个这样的方面对容量和代码设计的影响。这项研究的目的是描述新问题和解决方案的特征(例如，在对抗性攻击下计算通信速率的难度，不同网络流中冗余之间的交互，以及不一致的对抗性集合)，以及识别每个新场景中所需的解决方案之间的共性。然后，将这些共性应用于描述一般对抗性网络中安全和性能之间的基本权衡。这里使用的技术是通过归约，它通过证明一个问题的任何解决方案都可以用来构建另一个问题的解决方案，来说明两个问题之间的关系。具体地说，在具有由对手选择的状态的噪声网络和其相应的无噪声和无状态版本之间推导出约简，其容量更容易表征。此外，这些结果导致了所设计的安全编码策略的分析性能保证，从而为具体的设计方法和那些容量界限仍然开放的情况提供了指导。

Today's world is highly dependent on the integrity of communication systems as the Internet, WiFi, or cellular networks. As networks become more pervasive, they are increasingly being used for communication and storage of critical as well as sensitive data and therefore impose more stringent demands on reliability and security, which must be maintained even under extreme settings such as partial power failures, natural disasters, or, most importantly, adversarial attacks. This research seeks to understand fundamental limits of protecting complex practical networks against adversarial attacks, and how these limits can be achieved by optimal secure strategies, thus bridging the gap between advanced theoretical research and the development of realistic solutions. Further, the project is able to provide a significant transformative impact on many other critical applications employing reliable networked communications, for example in the fields of healthcare, environmental monitoring, finance, etc. It also provides a platform for creating broader technological, societal, research, and educational impact as advancing information technology and its benefits to society through newly established theory and practice, an ambitious education plan, and actively engaging students from underrepresented demographics.Specifically, the project focuses on aspects (e.g., distributed users, heterogeneity, delay requirements, actions of adversaries described by probability distributions) important in real network systems but poorly understood in current literature, and seeks to elucidate the impact of each such aspect on capacity and code design. This research aims both to characterize features of the problems and solutions (e.g., hardness of computing the rate of communication under adversarial attacks, interaction between redundancy in different network flows, and non-uniform adversarial sets) that are new to the literature, as well as to identify commonalities between the solutions required in each new scenario. These commonalities are then applied to characterize the fundamental tradeoff between security and performance in general adversarial networks. The technique employed here is via reductions, which demonstrate the relationship between two problems by showing that any solution for one can be employed to build a solution for the other. In particular, reductions are derived between noisy networks with a state chosen by the adversary and their corresponding noiseless and stateless versions, for which capacity is much easier to characterize. Further, these results lead to analytical performance guarantees for the designed secure coding strategies, thus providing guidance on specific design approaches and for those cases where capacity bounds are still open.