The flourish of 5th generation wireless systems (5G) network has brought numerous benefits to the Internet of Things (IoT) with universal connectivity, improved data rate, and decreased latency. The development of IoT extends the computation-intensive applications from centralized servers to the edge of the network, promoting the paradigm of edge computing. Edge computing brings great assistance to IoT architecture by efficiently accomplishing tasks with lower latency, less energy consumption and reduced network bandwidth. Edge-assisted IoT emerges to provide location-aware services and offload computational tasks to edge nodes near the IoT devices. However, a series of security challenges still exist in edge-assisted IoT owing to the inherent vulnerabilities of edge nodes and sensitive nature of the collected data. Among the emerging and existing security schemes in IoT applications, security and energy consumption are two overriding yet conflicting requirements. The tradeoff between security and energy is critical to the sustainability of the IoT ecosystem but still lacks sufficient discussion. In this article, we investigate the security challenges in edge-assisted IoT and how the constraints in energy consumption can affect the design of security schemes. Specifically, we firstly present the architecture of edge-assisted IoT and its unique characteristics. Secondly, we identify the security threats in the edge-assisted IoT applications and the security-energy tradeoff during implementation. Thirdly, in a case study of distributed denial of service (DDoS) and malware injection attack, we propose a preliminary solution to address the conflict between security and energy requirements. Finally, we discuss some open issues and identify future research directions for security and energy efficiency in edge-assisted IoT.

蓬勃发展的第五代无线系统（5G）网络通过通用连接，改进的数据速率和减少的延迟，为物联网（IoT）带来了许多好处。物联网的发展将计算密集型应用程序从集中式服务器扩展到网络边缘，从而促进了边缘计算的范式。边缘计算通过以较低的延迟，更少的能耗和更少的网络带宽有效地完成任务，为物联网架构带来了巨大的帮助。边缘辅助物联网的出现为人们提供了位置感知服务，并将计算任务转移给了物联网设备附近的边缘节点。但是，由于边缘节点的固有漏洞和所收集数据的敏感性质，边缘辅助物联网仍然存在一系列安全挑战。在物联网应用中新兴的和现有的安全方案中，安全性和能耗是两个最重要但又相互冲突的要求。安全与能源之间的权衡对于物联网生态系统的可持续性至关重要，但仍缺乏足够的讨论。在本文中，我们研究了边缘辅助物联网的安全挑战，以及能耗的限制如何影响安全方案的设计。具体而言，我们首先介绍了边缘辅助物联网的架构及其独特的特征。其次，我们确定了边缘辅助物联网应用程序中的安全威胁，以及在实施过程中的安全与能源之间的权衡。第三，以分布式拒绝服务（DDoS）和恶意软件注入攻击为例，我们提出了一个初步的解决方案来解决安全性和能源需求之间的冲突。最后，我们讨论了一些未解决的问题，并确定了边缘辅助物联网中安全性和能源效率的未来研究方向。