The consensus principle in blockchain refers to the way nodes in a decentralized network can agree on the state of the blockchain ledger and validate new transactions, without relying on a central authority.
Some key aspects of consensus principles in blockchain include:
Nodes follow a pre-defined protocol that specifies rules for consensus.
Special nodes called validators bundle transactions into blocks and verify their validity.
Validators apply cryptographic checks and protocol rules to reach an agreement.
Consensus is achieved once enough validators confirm a block is valid.
Finalized blocks are broadcast to all nodes who append it to their blockchain copy.
Consensus enables key properties like decentralization, security, transparency, and immutability in blockchains.
Different consensus mechanisms like PoW, PoS, DPoS, PBFT, etc. use varying approaches to facilitate node agreement in a trustless way.
But they all follow the core principle of nodes coordinating to verify transactions and agree on the blockchain state, without needing a central authority.