Abstract
The Internet of Things (IoT) has been widely used in every aspect of life. The rapid development of IoT technologies raises concerns regarding security and privacy. IoT security is a critical concern in the preservation of the privacy and reliability of users' private information. The privacy concern becomes the biggest barrier to further usage of IoT technology. This paper presents a review of IoT application areas in smart cities, smart homes, and smart healthcare that leverage such techniques from the point of view of security and privacy and present relevant challenges. In addition, we present potential tools to ensure the security and preservation of privacy for IoT applications. Furthermore, a review of relevant research studies has been carried out and discusses the security of IoT infrastructure, the protocols, the challenges, and the solutions. Finally, we provide insight into challenges in the current research and recommendations for future works. The reviewed IoT applications have made life easier, but IoT devices that use unencrypted networks are increasingly coming under attack by malicious hackers. This leads to access to sensitive personal data. There is still time to protect devices better by pursuing security solutions with this technology. The results illustrate several technological and security challenges, such as malware, secure privacy management, and non-security infrastructure for cloud storage that still require effective solutions.