In the Internet of Things vision, standard devices become sharp and self-administering. This vision is changing into a reality in view of advances in development, but there are still troubles to address, particularly in the security space e.g., data faithful quality. Considering the expected progression of the IoT before very long, it is critical to give trust in this tremendous moving toward information source. Blockchain has emerged as a key advancement that will change the way we share information. Building trust in dispersed conditions without the prerequisite for experts is a creative improvement that might perhaps change various organizations, the IoT among them. Problematic developments, for instance, large information and distributed computing have been used by IoT to overcome its limitations since its start, moreover, we think block chain will be one of the accompanying ones. This paper fixates on this relationship, investigates difficulties in block chain IoT applications.

Keywords : Blockchain, Internet-of-Things, IoT.