Cloud Computing (CC) is a promising technology due to its pervasive features, such as online storage, high scalability, and seamless accessibility, in that it plays an important role in reduction of the capital cost and workforce, which attracts organizations to conduct their businesses and financial activities over the cloud. Even though CC is a great innovation in the aspect of computing with ease of access, it also has some drawbacks. With the increase of cloud usage, security issues are proportional to the increase. To address these, there has been much work done in this domain, whereas research work considering the growing constrained applications provided by the Internet of Things (IoT) and smart city networks are still lacking. In this survey, we provide a comprehensive security analysis of CC-enabled IoT and present state-of-the-art in the research area. Finally, future research work and possible areas of implementation and consideration are given to discuss open issues.

The concept of smart cities is unique where the intelligent information technologies have used to form a heterogeneous with the help of edge and fog networks. Edge Computing (EC) has gained attention due to its distributive nature that brings computing resources closer to user devices for fast data communications. These networks are vulnerable to a variety of cyber threats due open network design and architecture and a lack of trusted computing resources. The Denial of Service (DoS) and Sybil attacks are common in these networks and cause of services degradation. Whereas in a Sybil attack, a node illegitimately claims multiple identities and escalate and launch more attacks in the networks. Identification and detection of malicious nodes and evaluating their trustworthiness is a challenging task. This paper proposes a novel Assertive Trust-based Efficient Technique (ATBET) for edge-based smart city networks by calculating the direct, indirect, penalized and cumulative trust. The trust is evaluated by using packet drop rate and the penalized over the transmission paths. The proposed solution detects the attacks and eliminates the malicious or selfish nodes from edge-based networks. The experiment results are conducted in simulation and compared proposed solution with state or the art solutions in terms of trustworthiness level, latency, packet delivery ratio, and network life span.