Privacy Enhancing Technologies in the Internet of Things: Perspectives and Challenges

Internet of Things (IoT) devices have brought much efficiency and convenience to our daily life. However, the devices may collect a myriad of data from people without their consent. Controlling the large amount of data generated from the devices from being misused is critical to mitigate privacy risks. Therefore, privacy protection on personal data has become an important factor in the development of the IoT. Historically, privacy enhancing technologies (PETs) can effectively enhance the privacy and protect users' personally identifiable information. To date, many researchers have stressed the importance of PETs and proposed solutions relevant to different application fields of the IoT. However, to the best of our knowledge, none of the research has analyzed the PETs in IoT from the aspects of privacy threat issues and privacy legislation. As a result, this paper surveys on the solutions of PETs in the field of IoT, which has filtered down from the large number of published academic papers to the 120 primary studies published between 2014 and 2017. After collecting the papers, we categorized them based on the functions and the coverage of privacy protection, and analyzed them from different aspects, ranging from high-level principles of general data protection regulations and ISO/IEC 29100:2011 requirements to the actual resolution of privacy threats in IoT. Thus, we aim to identify the current state of development of the PETs in various fields and examine whether the existing PETs comply with the latest legal principles and privacy standards and reduce the threats to privacy. Finally, recommendations for future research are given based on the results.