Blockchain Based Secure Communication for IoT Devices in Smart Cities

In smart city technologies we have witnessed advanced technological improvements in small computing devices, which can be connected to the Internet and named as Internet of Thing (IoT) devices, and cooperatively working complex systems. With this increased use of new technologies, the security problem is becoming more and more important because complex systems lead to unpredictable security vulnerabilities, which result in financial and private information losses. As a recently emerged technology, Blockchain was emerged as an alternative solution to security breaches of a different application environment. In contrast to the central structure used by most systems, it is preferred especially in the area of security by its distributed structure and the cryptographic hash algorithm it uses. Today, structures such as Smart Home, Smart City, Smart Environment and Smart Agriculture, which are created by using IoT are seen as active research areas with more security shortages. The reason for the security weakness in these areas arises from the hardware restriction on the IoT devices used. In the proposed system, an authorization system for IoT devices has been tried to be set up by using the distributed node structure of Blockchain system and blocks kept in these nodes. UDP (User Datagram Protocol), which uses a simple communication model without establishing a connection to the minimum protocol mechanism for communication of nodes in the system, was preferred. The communication between the nodes has been encrypted using encryption methods, thus creating a secure environment.