In blockchain technology, what does consensus refer to?

Consensus in blockchain technology refers to the method by which multiple nodes in a network agree on the validity of transactions. This is essential because blockchain operates in a decentralized manner without a central authority, and consensus ensures that all parties involved in the network have a uniform understanding of the current state of the ledger.

When a transaction is proposed, it cannot simply be added to the blockchain; instead, it must go through a consensus mechanism where the network participants validate the transaction according to predefined rules. This process prevents fraud and double-spending, ultimately ensuring the integrity and reliability of the entire blockchain.

While other choices touch on aspects of blockchain, they do not capture the core essence of what consensus means in this context. Transparency of transactions is important, but it is not the same as reaching an agreement regarding their validity. Similarly, syncing ledgers across nodes and adding new nodes are operational tasks that support the network but do not define the concept of consensus itself.