Consensus

Bitcoin uses the proof-of-work mechanism to prevent malicious users from spending Bitcoins they don't have. However, its mechanism is costly and slow since it uses an immense amount of energy. Ripple came up with a consensus mechanism that is cheaper and faster.

In order to validate a transaction, Ripple doesn't rely on central authority. Instead, it has made a set of rules that the nodes in the network must follow to agree and reach on a consensus on what must go on the permanent ledger. This set of rules are called the consensus protocol.