The recently accentuated features of augmenting conventional wireless networks with high altitude platform systems (HAPS) have fueled a plethora of applications, which promise to offer new services to ground users, as well to enhance the efficiency and pervasion of existing applications. Cloud-enabled HAPS, which aims to create HAPS-based datacenters that offer cloud services to users, has particularly emerged as a promising key enabler to provide large-scale equitable services from the sky. Although offering cloud services from the HAPS proves to be efficient, its practical deployment at the stratosphere level still faces many challenges such as high energy requirements, physical maintenance, and is particularly prone to security considerations. Safeguarding the cloud-enabled HAPS against various cyberattacks is a necessity to guarantee its safe operation. This paper proposes a blockchain model to secure cloud-enabled HAPS networks that contain a large number of HAPS stations from recurring cyberattacks within the context of the environment and infrastructure monitoring (EIM) application. To this end, the paper first presents a detailed blockchain framework, and describes the ways of integrating the developed framework into the various system components. We then discuss the details of the system implementation, including the storing and consuming of cloud transactions, the generation of new blocks, and the blockchain consensus protocol that is tailored to the EIM requirements. Finally, we present numerical simulations that illustrate the performance of the system in terms of throughput, latency, and resilience to attacks.

翻译：近期，利用高空平台系统（HAPS）增强传统无线网络的特性日益凸显，催生了众多应用场景。这些应用不仅有望为地面用户提供新服务，还能提升现有应用的效率与普及度。其中，云使能HAPS系统旨在构建基于HAPS的数据中心，向用户提供云服务，已成为从空中提供大规模公平服务的关键使能技术。尽管从HAPS提供云服务被证明高效，但其在平流层的实际部署仍面临诸多挑战，如高能耗、物理维护困难，尤其易受安全威胁影响。保障云使能HAPS免受各类网络攻击对其安全运行至关重要。本文针对环境与基础设施监测（EIM）应用场景，提出了一种用于保护包含大量HAPS站的云使能HAPS网络免受频繁网络攻击的区块链模型。为此，本文首先详细阐述了区块链框架，并描述了将所开发框架集成至系统各组件的具体方法。随后，我们讨论了系统实现细节，包括云交易的存储与消费、新区块的生成，以及针对EIM需求定制的区块链共识协议。最后，通过数值仿真展示了系统在吞吐量、延迟及抗攻击韧性方面的性能表现。