Technologies shaping the future, Internet of Things (IoT) and Big Data, are the leading research topics in the computer science department. Every field like this is prone to attacks from hackers and adversaries, which is why there is a need for proper security method implementations. The current nature of the Internet of Things uses centralized servers for data collection and analysis requirements, which invites many security concerns. Similarly, big data deals with a huge amount of data that is processed and analyzed every day. The blockchain network can fill this need for a better security solution. Even though it is in its infancy but due to the features, such as Decentralization, Persistency, Anonymity, and Auditability, it is able to strengthen the security of the various IoT and big data applications. This paper discusses the security flaws in the existing centralized infrastructure used by the above technologies and presents the security solution to solve the flaws.