Internet of Things and Blockchain Integration: Security, Privacy, Technical, and Design Challenges

 The Internet of things model enables a world in which all of our everyday devices canbe integrated and communicate with each other and their surroundings to gather and share dataand simplify task implementation. Such an Internet of things environment would require seamlessauthentication, data protection, stability, attack resistance, ease of deployment, and self-maintenance,among other things. Blockchain, a technology that was born with the cryptocurrency Bitcoin, mayfulfill Internet of things requirements. However, due to the characteristics of both Internet of thingsdevices and Blockchain technology, integrating Blockchain and the Internet of things can cause severalchallenges. Despite a large number of papers that have been published in the field of Blockchain andthe Internet of things, the problems of this combination remain unclear and scattered. Accordingly,this paper aims to provide a comprehensive survey of the challenges related to Blockchain–Internet ofthings integration by evaluating the related peer-reviewed literature. The paper also discusses someof the recommendations for reducing the effects of these challenges. Moreover, the paper discussessome of the unsolved concerns that must be addressed before the next generation of integratedBlockchain–Internet of things applications can be deployed. Lastly, future trends in the context ofBlockchain–Internet of things integration are discussed.