ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT Securing the Internet of Things: Challenges, Threats and Solutions Panagiotis I. Radoglou Grammatikis a , Panagiotis G. Sarigiannidis a,* , Ioannis D. Moscholios b a Department of Informatics and Telecommunication Engineering, University of Western Macedonia, Kozani, Greece b Department Informatics and Telecommunications, University of Peloponnese, Tripolis Greece Abstract The Internet of Things (IoT) is the next technological leap that will introduce significant improvements to various aspects of the human environment, such as health, commerce, and transport. However, despite the fact that it may bring beneficial economic and social changes, the security and the privacy protection of objects and users remain a crucial chal- lenge that has to be addressed. Specifically, now the security measures have to monitor and control the actions both of users and objects. However, the interconnected and independent nature of objects, as well as their constrained capabilities regarding the computing resources make impossible the applicability of the conventional security mechanisms. Moreover, the heterogeneity of various technologies which the IoT combines increases the complexity of the security processes, since each technology is characterized by different vulnerabilities. Fur- thermore, the tremendous amounts of data which is generated by the multiple interactions between the users and objects or among the objects make harder their management and the functionality of the access control systems. In this context, this paper intends to pro- vide a comprehensive security analysis of the IoT, by examining and assessing the potential threats and countermeasures. More detailed, after studying and determining the security requirements in the context of the IoT, we implement a qualitative and quantitative risk analysis, investigating the security threats per layer. Subsequently, based on this process we identify the suitable countermeasures and their limitations, paying special attention to the IoT protocols. Finally, we provide research directions for future work. Keywords: Countermeasures, Cyberattacks, Internet of Things, Privacy, Protocols, Risk Assessment, Security 1. Introduction The IoT represents a technologically optimistic future, where the objects will be able to utilize the Internet and make intelligent collaborations with each other anywhere and * Corresponding Author Email addresses: pradoglou@uowm.gr (Panagiotis I. Radoglou Grammatikis), psarigiannidis@uowm.gr (Panagiotis G. Sarigiannidis), idm@uop.gr (Ioannis D. Moscholios) Preprint submitted to Internet of Things November 29, 2018