The proliferation of resource-constrained devices has become prevalent across various digital applications, including smart homes, smart healthcare, and smart transportation, among others. However, the integration of these devices brings many security issues. To address these concerns, Blockchain technology has been widely adopted due to its robust security characteristics, including immutability, cryptography, and distributed consensus. However, implementing blockchain within these networks is highly challenging due to the limited resources of the employed devices and the resource-intensive requirements of the blockchain. To overcome these challenges, a multitude of researchers have proposed lightweight blockchain solutions specifically designed for resource-constrained networks. In this paper, we present a taxonomy of lightweight blockchain solutions proposed in the literature. More precisely, we identify five areas within the "lightweight" concept, namely, blockchain architecture, device authentication, cryptography model, consensus algorithm, and storage method. We discuss the various methods employed in each "lightweight" category, highlighting existing gaps and identifying areas for improvement. Our review highlights the missing points in existing systems and paves the way to building a complete lightweight blockchain solution for networks of resource-constrained devices.

翻译：资源受限设备的广泛普及已渗透至各类数字应用领域，包括智能家居、智慧医疗与智能交通等。然而，这些设备的集成带来了诸多安全问题。针对这些隐患，区块链技术因其不可篡改性、密码学机制与分布式共识等强安全特性而被广泛采用。但由于部署设备资源有限与区块链本身的高资源需求，在该类网络中实施区块链面临极大挑战。为突破这些障碍，众多研究者提出了专为资源受限网络设计的轻量级区块链解决方案。本文对现有文献中提出的轻量级区块链方案进行了分类体系构建。具体而言，我们识别出"轻量化"概念下的五个核心领域：区块链架构、设备认证、密码学模型、共识算法与存储方式。我们系统论述了每个"轻量化"类别中采用的不同方法，揭示了现有空白并指出了改进方向。本综述通过揭示现有系统的缺陷，为构建面向资源受限设备网络的完整轻量级区块链解决方案指明方向。