Fog computing refers to cloud computing development to the edge of a corporate network. Fog computing, as a promising computing paradigm, facilitates computing, storing and network services between terminal devices and cloud computing data centers. It also brings many advantages to cloud computing and large-scale deployment of IoT applications such as low latency, data locality, location-awareness, mobility, less computational cost and geographical distribution. This extensive range of functionality raises various security concerns related to data, virtualization, segregation, network communication and monitoring. Security is a significant issue for fog computing since fog-based services are offered to massive-scale end-users by front fog nodes/servers. Also, fog computing focuses on ensuring the availability and reliability of services without worrying about the information stored or processed by the fog. Despite significant efforts that have been made in this field, many issues are still open. This paper prepares a comprehensive study of security challenges and different approaches in fog computing to address those challenges using the Systematic Literature Review (SLR) approach. Moreover, a technical taxonomy is offered for the fog security challenges and their strategies in terms of six aspects, including reliability, access control, attacks, secure connection, privacy and some special cases. The core objective of this study is to analytically and statistically classify the existing research techniques related to security aspects and available solutions in fog computing published between 2014 and 2021. Then some technical questions in this domain are provided, and also the strengths and weaknesses of each indicated fog security approach are discussed based on the questions, as well as suggesting some ideas to address security deficiencies in fog computing. Finally, some future motivational directions and open issues in this field are provided to design, implement, and maintain fog systems.

雾计算是指云计算向企业网络边缘发展。雾计算作为一种很有前途的计算范式，促进了终端设备与云计算数据中心之间的计算、存储和网络服务。它还为云计算和物联网应用的大规模部署带来了许多优势，例如低延迟、数据本地化、位置感知、移动性、更少的计算成本和地理分布。这种广泛的功能引发了与数据、虚拟化、隔离、网络通信和监控相关的各种安全问题。安全性是雾计算的一个重要问题，因为前雾节点/服务器向大规模最终用户提供基于雾的服务。还，雾计算侧重于保证服务的可用性和可靠性，而不用担心雾存储或处理的信息。尽管在该领域做出了重大努力，但仍有许多问题悬而未决。本文准备对雾计算中的安全挑战和不同方法进行全面研究，以使用系统文献综述 (SLR) 方法解决这些挑战。此外，从可靠性、访问控制、攻击、安全连接、隐私和一些特殊情况等六个方面为雾安全挑战及其策略提供了技术分类。本研究的核心目标是对 2014 年至 2021 年间发布的与安全方面相关的现有研究技术和雾计算可用解决方案进行分析和统计分类。然后提供该领域的一些技术问题，以及每种技术的优缺点基于这些问题讨论了指定的雾安全方法，并提出了一些解决雾计算安全缺陷的想法。最后，为设计、实现和维护雾系统提供了该领域未来的一些激励方向和未解决的问题。以及提出一些解决雾计算安全缺陷的想法。最后，为设计、实现和维护雾系统提供了该领域未来的一些激励方向和未解决的问题。以及提出一些解决雾计算安全缺陷的想法。最后，为设计、实现和维护雾系统提供了该领域未来的一些激励方向和未解决的问题。