Why the XRP Ledger and Avalanche Consensus Protocols have the best designs and the potential to lead the industry over the long term.
A consensus protocol is an algorithm that is used to get nodes in a decentralized system to agree on the next valid state. In simple terms, consensus is the task of getting a group of computers to come to an agreement on a decision.
There have been just three main approaches to the consensus problem throughout the history of distributed systems: Classical, Nakamoto, and recently, Avalanche.
It's possible that you've heard of Proof-of-Work or Proof-of-Stake being referred to as consensus algorithms. But they are not, they are often referred to as such for simplicity; they're Sybil resistance mechanisms (SRMs). SRMs are used to deter against Sybil attacks.
A SRM isn't sufficient on its own to achieve consensus. It must be used in conjunction with a consensus algorithm. A Sybil attack is when a single node can flood the network using multiple identities to pretend to be multiple nodes and use them to gain a disproportionately large influence. Ideally, in a decentralized system, we want each node to represent 1 vote. If a node can pretend to be many different nodes and gain multiple votes instead, then it makes the system susceptible to attacks. The SRM is here to prevent this.
In 2012, the XRP Ledger developers pioneered the Federated Byzantine Agreement (FBA), a consensus protocol that is inspired by the Classical Consensus but with some modifications, and based on the Byzantine fault tolerance mechanism.
FBA is used for its high throughput, network scalability, and low transaction costs. In FBA-based systems anyone can participate as a node with low barriers and decentralized control. Nodes choose who they can trust.
Individual nodes make decisions that create system-wide quorums. The number of nodes required to reach agreement within a system is known as a quorum. FBA systems use the term "quorum slices" - a subset of a quorum that can persuade another relevant node to agree.
An FBA system may be up to date and accurate without requiring all of its nodes to agree. The ability to choose whom each node trusts decentralizes the network. For a transaction to be approved on the XRP Ledger, the ledger requires at least 80% quorum approval.
This means that the XRP Ledger is not vulnerable to a 51% attack because it does not use mining in its consensus algorithm. Proof-of-Work was the first mechanism to solve the double spend problem without requiring a trusted third party.
The XRPL's consensus protocol solves the same problem in a far faster, cheaper and more energy efficient way. Since 2012, the XRPL has proven that the blockchain trilemma doesn't exist if the network and consensus protocol are properly and carefully designed.
Then in 2018, a new type of consensus algorithm was introduced, called Avalanche Consensus. Following in Nakamoto's footsteps, the developers wanted to develop an algorithm that offered all of the advantages of Nakamoto Consensus (robustness, scale, decentralization), as well as all of the advantages of Classical consensus (speed, quick finality, and energy efficiency).
Participants in Avalanche build confidence in the correct decision propagated by all nodes in the network after a validator picks other validators at random to inquire about their preferences.
With enough confidence, a decision is finalized immediately. Unlike the Nakamoto Consensus, Avalanche does not depend on Proof-of- Work. In networks like Bitcoin, Proof-of-Work is necessary for both organization and security against bad actors.
Although PoW could be utilized with Avalanche Consensus, Proof-of-Stake was chosen to force users to have an amount of tokens before being allowed to vote on transactions. Finally, Avalanche nodes operate only when there is work to be done, unlike Bitcoin and other systems based on Nakamoto's invention that necessitate continual action. There is no mining or polling involved in obtaining new blocks. Avalanche launched in 2020 and since then it has proven to be one of the most stable, efficient and decentralized systems.
Conclusion: The mechanics of both the XRPL and Avalanche are amazing and have proven to be resilient with the potential to lead the blockchain future. It's the main reason why my top 2 crypto and bluechips are
$XRP and
$AVAX.