WHAT IS THE RIPPLE PROTOCOL CONSENSUS? (RPCA)
The functional value of any crypto asset shines through the consensus protocol of its underlying blockchain network. Essentially, the consensus protocol is the process through which the different nodes on a blockchain network agree to validate a set of transactions by adding them as a block to the growing chain. Therefore, the consensus algorithm is crucial for deciding how secure, scalable and decentralized a cryptocurrency actually is.
The Ripple Protocol Consensus Algorithm (RPCA) is a democratic consensus achieved amongst a pre-assigned Unique Node List (UNL) instead of involving every individual node. This Unique Node List is a subset of the Ripple Network, which is considered trustworthy enough to validate transactions. The RPCA executes in rounds, where transactions waiting for confirmation must be validated by at least 80% of the UNL servers. Basically, the Ripple network is able to execute transactions in an extremely fast yet secure manner by only requiring consensus from a trusted subset of the network rather than querying every node.
Those who appreciate the decentralized nature of cryptocurrency and blockchain might be seeing a major tradeoff with this approach. By authorizing a certain subset of nodes over others, the Ripple Network is employing a hierarchical system to process transactions. One could argue through this process, the decentralized characteristics of this blockchain are diminished.