Smart devices have dominated the 21st century with almost everyone using some type of smart gadget on a daily basis. Importantly, all kinds of smart devices store user’s data which can potentially risk the user’s privacy; as such with the increasing number of data breaches occurring with technological advancements of these devices, there is an element of lack of trust for data security. This imposes a major security concern for the users. To address such data security concerns, risks and issues, Blockchain technology offers reliable data management where the data is the property of the user. This can be highly applicable for IoT integration of Smart Cities. Blockchain with IoT data in smart cities for large data processing and predictive analytics is undoubtedly the way to the future and one of the key interest areas of MDAR group.