The Stellar Consensus Protocol | David Mazières | Talks at Google

Crap. I'll reproduce the answer here, then: > Tl;dr: Stellar’s protocol (SCP) uses a decentralized state propagation where each node commits to a value if every node it deems trustworthy agrees while Ripple uses a supermajority vote (80%) among all validating nodes. Stellar achieves better decentralization than Ripple > A pretty old, but still relevant discussion on the bitcoin stack exchange [ link ] > Stellar started out as a fork of Ripple (now completely rewritten) so they are pretty similar in implementation and use cases. > Stellar uses the Stellar Consensus Protocol [ link ] (SCP) to achieve decentralization, while Ripple uses the XRP Ledger Consensus Process [ link ]. These are alternatives to Bitcoin's proof of work whose goal is to have every participant in the network agree on the current state. > In SCP, each node decides for itself which other nodes it trusts. When a lot of these sets of trusted nodes are overlapping, there is a high probability there is agreement on the state of the network. Broadly, a node will only accept a message if all of their trustworthy nodes have in turn accepted it. This is similar to the way internet certificates and DNS servers are working. In principle, there is no central authority appointing trustworthy nodes, but de facto, the network will reach an agreement on which nodes are trustworthy. This is a great video explaining SCP in detail [ this video ]. There is also the white paper [ link ] for more formal mathematical defini

David Mazières (designer of the protocol) has given a number of talks. Here's a good video of his talk at Google, and I believe it's the one I watched a couple years ago: this video