What is a Bitcoin full node?

A Bitcoin full node is a complete implementation of the Bitcoin protocol that stores the entire history of Bitcoin transactions and actively participates in the network by verifying transactions and blocks.

Here's what it does:

1. **Stores the Blockchain**: It maintains a complete copy of the Bitcoin blockchain, which is essentially a public ledger containing records of all transactions ever made in the Bitcoin network.

2. **Verifies Transactions**: Full nodes validate transactions by ensuring they adhere to the consensus rules of the Bitcoin protocol. This includes checking that transactions are properly signed, that the inputs are unspent, and that the total outputs do not exceed the inputs.

3. **Broadcasts Transactions**: Full nodes share newly broadcasted transactions with other nodes in the network, helping to propagate transactions quickly.

4. **Participates in Consensus**: Full nodes participate in the consensus mechanism of Bitcoin by validating and relaying blocks. They ensure that the longest valid chain of blocks is the one accepted by the network, helping to maintain the integrity and security of the blockchain.

5. **Enhances Network Decentralization**: By running a full node, individuals contribute to the decentralization of the Bitcoin network. More full nodes mean more redundancy and resilience against attacks or failures.

Running a full node requires significant computational resources and storage space, but it provides users with enhanced security and privacy, as they don't need to rely on third-party services to verify transactions.