A Light Node is a type of node that connects to a blockchain network but downloads and stores only a partial copy of the ledger, relying on a Full-Node to provide validation and security.

A Lightweight Way to Join the Network

Running a full-node requires a significant amount of computing power and storage, as it must download and store the entire history of a blockchain. This can be a barrier to entry for many users. A light node was developed as a solution to this problem.

Instead of downloading the entire ledger, a light node only downloads the block headers, which contain a summary of the transactions in each block. When a light node needs to verify a transaction, it queries a full-node for a small piece of data that proves the transaction's validity. This process is much faster and requires significantly less storage space, making it ideal for devices like mobile phones and tablets.

The Trade-Offs

The main advantage of a light node is its convenience and low resource requirements. However, this comes with a trade-off: a light node must trust the data provided by a full-node. If a malicious full-node were to provide false data, a light node would not be able to independently verify it. This is why it is so crucial for a blockchain to have a large number of honest, independent full nodes to ensure the security of the network as a whole.