Industry 4.0 includes that components such as artificial intelligence, big data, autonomous systems, human-robot interaction, and the internet of things. Because of these components; some benefits are aimed, such as minimizing human impact, reducing costs, and increasing business volume. It is seen that the most fundamental problem of Internet of Things (IoT) technology, which is one of the basic concepts of Industry 4.0, is security. In recent years, blockchain architectures have been trying to find a solution to this problem. This study focuses on blockchain architectures used in the IoT ecosystem.