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Comparison and evolution of consensus mechanisms - PoW, PoS, DPoS, BFT, Rollup - web3 series Section 14

2025-08-267 Minute

When I first came into contact with the blockchain, the most discussed topic was “Bitcoin mining”, which is actually a manifestation of the consensus mechanism. As the industry develops, more and more consensus mechanisms are emerging, not only to improve efficiency, but also to reduce energy consumption and enhance security. Today we will talk about several mainstream consensus mechanisms: PoW, PoS, DPoS, BFT, and Rollup related to expansion.

PoW (Proof of Work): The starting point of blockchain

PoW is the earliest consensus mechanism adopted by Bitcoin. It uses "computing power competition" to ensure transaction security and data cannot be tampered with.

Features:

High security: You need to master more than 51% of the computing power to attack the network.
High energy consumption: Consumes a lot of power.
Confirmation speed is slow: Bitcoin produces a block every 10 minutes on average.

👉Case 1: Bitcoin mining energy consumptionAccording to 2022 data from the University of Cambridge, the annual electricity consumption of the entire Bitcoin network is approximately equal to the national electricity consumption of a medium-sized country (such as Argentina). This is why PoW has always been controversial.

Inspire: PoW has strong security, but is not suitable for application scenarios that require high performance and low energy consumption.

PoS (Proof of Stake): a new way to save energy

PoS participates in consensus by "pledged tokens". Whoever pledges more coins and holds them for a longer time will be more likely to obtain accounting rights.

Features:

Energy saving and environmental protection: Does not rely on computing power, but on currency holdings.
Performance improvements: Block generation is faster.
There is a "Matthew Effect": People who hold more coins are more likely to receive rewards.

👉Case 2: Ethereum Merge (The Merge)In 2022, Ethereum will switch from PoW to PoS, directly reducing energy consumption99.95%. This makes Ethereum more suitable for hosting large-scale applications such as DeFi and NFT.

Inspire: PoS reduces energy consumption while taking into account security and efficiency, and is suitable for long-term development.

DPoS (Delegated Proof of Stake): More efficient governance

DPoS is an improved form of PoS in which token holders elect representative nodes to perform accounting and maintain the network.

Features:

Fast block generation: Usually a block of several seconds.
Governance structure is clearer: Representative nodes are elected by community voting.
There is a risk of centralization: If a few representatives control the network, the degree of decentralization will decrease.

👉Case 3: EOS’s DPoS modelEOS uses 21 super nodes to produce blocks, one block every 0.5 seconds. Although the performance is very strong, it has also been criticized for "too concentrated nodes".

Inspire: DPoS is suitable for applications that require high performance, but governance transparency and decentralization need to be balanced.

BFT (Byzantine Fault Tolerance): Guarantee of Consistency

BFT-like algorithms originated from distributed systems and were used to solve the "Byzantine Generals Problem". In the blockchain, BFT ensures that consensus can be reached even if some nodes are malicious.

Features:

Quick confirmation: Consensus is reached within seconds.
Suitable for small-scale networks: Such as alliance chain and private chain.
Limited scalability: When the number of nodes is large, the communication complexity increases.

👉Case 4: Tendermint (used by Cosmos)Tendermint uses the BFT algorithm and can confirm transactions within seconds, making it very suitable for cross-chain and application chain scenarios.

Inspire: BFT is more suitable for alliance chains and application chains, rather than large-scale public chains.

Rollup: the “expansion partner” of the consensus mechanism

Strictly speaking,Rollup is not a consensus mechanism, but a Layer 2 expansion solution. But it is closely related to the consensus mechanism, because it processes most transactions off-chain and then submits them to the main chain uniformly.

type:

Optimistic Rollup: Assuming the transaction is valid, if anyone questions it, submit the proof again.
ZK Rollup: Use zero-knowledge proof to ensure transaction correctness.

Advantages:

TPS greatly improved: Increased from 15 on the Ethereum main chain to thousands.
Gas cost reduction: The cost of a single transaction has dropped by more than 90%.
Security relies on the main chain: It is ultimately confirmed by the main chain.

👉Case 5: Arbitrum and ZKSyncArbitrum (Optimistic Rollup) is widely used in DeFi applications; while ZKSync (ZK Rollup) is gradually becoming popular in NFT transactions and cross-border payments. Both are solving the pain point of high gas in Ethereum.

Inspire: Rollup is not a replacement for consensus, but a supplement, allowing the main chain to improve scalability while maintaining security.

Frequently Asked Questions (FAQ)

Q: Why is PoW considered "the most secure"?

A: Because the attacker needs to control more than half of the computing power, the cost is extremely high. This has kept Bitcoin solid for more than a decade.

Q: Will PoS be "monopolized by the rich"?

A: There is such a risk. In order to avoid this, many projects introduce "randomness" and "penalty mechanisms" to break the monopoly.

Q: What is the difference between DPoS and PoS?

A: DPoS is an improved version of PoS. It adds a voting mechanism and allows a small number of representative nodes to be responsible for producing blocks, which improves efficiency.

Q: Will Rollup replace the main chain?

A: No. Rollup is an expansion solution that relies on the security of the main chain. It is essentially an "enhancement", not a replacement.

Summarize

From the computing power competition of PoW, to the staking mechanism of PoS, to the representative governance of DPoS and the rapid consensus of BFT, and finally to the expansion assistance of Rollup, the consensus mechanism has been evolving. There is no "absolute good or bad" between them, but they are suitable for different application scenarios.

My personal understanding is: if you want the highest security, PoW is still the first choice; if you pursue performance and environmental protection, PoS and DPoS are more suitable; BFT is commonly used in alliance chains; and to deal with main chain congestion, Rollup is the best partner. In the next few years, we may see multiple consensus mechanisms and expansion solutions coexisting in parallel, jointly promoting Web3 applications to become mainstream.

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