Internet of Things devices provide data from existing sensors and usually have limited resources from computing performance to storage. That happens because IoT devices are required to be able to save much energy as possible, so the network lifetime of the IoT devices will be more optimal. The limitations of computing and storage reduce the level of security and trust in the IoT network environment itself. Blockchain can guarantee data security and reliability, as well as solve security problems in the IoT network. There is some research focused on modifying blockchain without eliminating security features and data reliability. This technology can be applied to the IoT network. This type of blockchain is usually called a lightweight blockchain. For example, a lightweight blockchain called LightChain, it modifies Proof-of-Work consensus algorithm. It is reported the use of this modified consensus algorithm can reduce computing power by 39.32%. This study will show some lightweight blockchain concepts that exist today and allow them to be applied in conjunction with IoT technology.