Federated Byzantine Agreement (FBA)

A Federated Byzantine Agreement (FBA) is a form of Byzantine fault tolerance where each byzantine general is responsible for their own blockchain. A Federated Byzantine Agreement (FBA) is used for its high throughput, network scalability, and low transaction costs. Notable cryptocurrencies using the Federated Byzantine Agreement (FBA) include Stellar and Ripple. Stellar was the first cryptocurrency to successfully implement a safe and secure Federated Byzantine Agreement (FBA), even though FBA consensus mechanism was pioneered by Ripple.

Federated Byzantine Agreements (FBA) require nodes to be known and verified ahead of time before users request any performance from the FBA. The nodes also choose who they trust, and eventually quorums of nodes emerge from decisions made by the individuals nodes making up the FBA network. A quorum is the minimum number of nodes required for a solution to be correct, and after a quorum forms the block is validated and included on the blockchain. The FBA uses 'quorum slices', which are subsets of quorums that can convince specific nodes operating on the network to agree with them.