A consensus mechanism is a self-regulatory stack of software protocols written into a blockchain's code that synchronizes a network into agreement about the state of a digital ledger.
Consensus mechanisms are algorithms used by blockchain networks to achieve agreement among nodes on the state of the ledger, ensuring;
1. Security
2. Integrity
3. Immutability
Types of Consensus Mechanisms
Proof-Based Mechanisms
1. Proof of Work (PoW): Bitcoin, Ethereum (pre-Merge)
1. Energy-intensive, slow
2. Proof of Stake (PoS): Ethereum (post-Merge), Solana
1. Less energy-intensive, faster
3. Delegated Proof of Stake (DPoS): EOS, Tron
1. Centralized
4. Leased Proof of Stake (LPoS): NEO
1. Variation of PoS
Voting-Based Mechanisms
1. Byzantine Fault Tolerance (BFT): Ripple
1. Fast, energy-efficient
2. Federated Byzantine Agreement (FBA): Stellar
1. Variation of BFT
3. Leader-Based Byzantine Fault Tolerance (LBBFT)
1. Improved BFT
DAG-Based Mechanisms
1. Directed Acyclic Graph (DAG): IOTA, Nano
1. Fast, energy-efficient
2. Tangle: IOTA
1. Variation of DAG
3. Mysticeti: Sui
1. Novel, high-performance
Hybrid Mechanisms
1. Proof of Activity (PoA): Decred
1. Combines PoW and PoS
2. Proof of Capacity (PoC): Burstcoin
1. Variation of PoS
Comparison
| Mechanism | Security | Scalability | Energy Efficiency |
| --- | --- | --- | --- |
| PoW | High | Low | Low |
| PoS | Medium | Medium | High |
| DPoS | Medium | High | High |
| BFT | High | High | High |
| DAG | High | High | High |
Considerations
1. Security: Resistance to attacks
2. Scalability: Transaction capacity
3. Energy efficiency: Environmental impact
4. Complexity: Implementation difficulty
5. Centralization: Node distribution
