Internet of Things (IoT) is a promising networking scenario in the cyber world, bridging physical devices and virtual objects. By considering the limited capacity of smart things, cloud computing is generally applied to store and process the massive data collected by the IoT. Furthermore, fog computing is described as an extension and a complement to cloud computing. It utilises fog nodes to perform storage, computation, and communication locally. The merging of cloud/fog computing and IoT can be seen as the best of two worlds by concurrently offering ubiquitous sensing services and powerful processing capabilities.

Despite the advantages of cloud/fog-assisted IoT, it is unwise to neglect the significance of security and privacy in this highly heterogeneous and interconnected system. Various solutions have recently been put forward independently for cloud, fog, or IoT environments to deal with security threats to IoT devices and sensitive data. However, a few crucial features, such as heterogeneity and scalability, have not been appropriately considered in these solutions.

The objective of this Special Issue is to compile recent research efforts dedicated to studying the security and privacy of rapidly increasing cloud/fog-assisted IoT applications. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Security and protection architectures for cloud/fog-assisted IoT
• Novel architectures, concepts, and models in cloud/fog-assisted IoT security
• Cryptography protocols and algorithms for cloud/fog-assisted IoT
• Threat models and attack strategies for cloud/fog-assisted IoT
• Threat detection/prevention methods in cloud/fog-assisted IoT
• Authentication methods in cloud/fog-assisted IoT
• Machine and deep learning for solving security in cloud/fog-assisted IoT
• Blockchain technology in cloud/fog-assisted IoT
• Federated models for privacy and security of cloud/fog-assisted IoT services
• Big data analytics for heterogeneous cloud/fog-assisted IoT systems
• State-of-the-art reviews on security and privacy for cloud/fog-assisted IoT