YouTube review: https://youtu.be/AdNdmwGkjsU Due to the centralization design of traditional IoT architecture, the users’ behavioral data is stored in the center servers controlled by merchants. Thus, the users’ data is prone to be leaked out and the users’ privacy as well as safety will face severe threats. The blockchain has provided decentralized ideas and technology, which are very suitable for the self-service, self-maintenance, self-transactions and shares between machines in IoT industry  . But there are still some key problems to be solved when applying the blockchain technology in IoT, This is where IoT Chain comes into play Some of the problems are the forming of consensus, quick pay on small amount and protection of data privacy. For these problems, IoT has brought up its own solutions, including PBFT, SPV, DAG, CPS cluster technology, big-data analysis smart contract ChainCode and so on. ITC adopts the main chain of PBFT consensus, the DAG network, which supports high performance by nature, as side chain and the multi-tier architecture to build an IoT operating system which is safe, decentralized and can support high concurrency.