Ensure all copies of the blockchain are the same, the network uses consensus mechanisms, such as Proof of Work (PoW) or Proof of Stake (PoS), to agree on the validity of transactions and the addition of new blocks How Does a blockchain work .

Each block contains a unique hash of its contents. This hash acts as a digital fingerprint, and any change in the block’s data will result in a different hash, making tampering easily detectable.