Introduction#
In the Web3 ecosystem, is there one "blockchain" or many? We often hear about Bitcoin, Ethereum, and a bunch of new terms like Solana, Arbitrum, Polygon, BNB Chain...
Chains, Not Just One#
"Blockchain" is not a specific thing; it's a technical architecture. Just like "blog" is a form of website, but can specifically be Zhihu, Sina Weibo, WordPress, or even Xiaohongshu.
So in the Web3 world, there are many blockchains, and different projects and developers can build their own chains within this framework, each with its own characteristics, operation methods, and user groups.
How are these chains classified? The simplest way: divided into three categories based on "openness":
Public Chain#
This is the type of chain we encounter the most, such as:
- Bitcoin
- Ethereum
- Solana
- Avalanche
The characteristic is completely open, anyone can participate; you can download a wallet, view data, and deploy contracts without needing to register or apply for permission. They are also the main battleground for Web3 applications.
However, because everyone can use them, there are many transactions, high load, and performance is relatively average (slow speed, high fees).
Private Chain#
Simply put, this is a chain used "internally by a company," which outsiders cannot see or participate in. For example, a logistics company uses blockchain to track packages, but this chain only allows employees or partners to access it.
The advantages are speed and security; the disadvantages are excessive "centralization" and privatization.
Consortium Chain#
This is in between the two. For example, several banks or companies come together to build a chain, jointly maintaining nodes, but it is not open to the public. Alibaba's "Ant Chain" and some multinational organizations' "Hyperledger" belong to this category.
Different Chains, How to Maintain "Consensus"?#
Regardless of which chain it is, the most important question is: how do people decide "which transaction is real"?
This involves the "consensus mechanism."
In simple terms, it is who has the right to "keep the ledger" and "how to select this person."
PoW: Competing Computing Power, Who's Fast Wins (Bitcoin)#
The earliest consensus mechanism, Proof of Work, is where miners compete to solve problems; whoever solves it first packages the transaction and receives a reward.
- ✅ Secure, very high cost of cheating
- ❌ Wastes resources, generates heat, consumes electricity, slow speed
As mentioned in the article "What the Heck is Web3?," Bitcoin uses PoW.
PoS: Staking Coins, The More You Have, The More Power You Get (Ethereum)#
Proof of Stake looks at who has staked the most coins. The more you stake and the longer you stake, the more likely you are to be selected to package transactions.
- ✅ Energy-efficient, high efficiency
- ❌ Has a bit of a "wealthy people rule" flavor
Since Ethereum's merge, it has transitioned from PoW to PoS, making it the most active PoS public chain.
DPoS / PoA: A Few Decide, Efficiency Maximized#
- DPoS (Delegated Proof of Stake): Users vote to elect representatives to package transactions, such as EOS
- PoA (Proof of Authority): Select a few "trusted nodes" to be responsible for keeping the ledger, such as the testnet of BNB Chain
This type of mechanism basically sacrifices decentralization for throughput and transaction speed.
Mainstream Public Chain Consensus Quick Reference Table#
| Chain | Consensus Mechanism | Characteristics | Use Cases |
|---|---|---|---|
| Bitcoin | PoW | Most decentralized, strongest against censorship | Value storage |
| Ethereum | PoS | Most prosperous ecosystem, supports smart contracts | DeFi, NFT |
| Solana | PoS + PoH | Fast speed, good on-chain experience | Chain games, NFT |
| BNB Chain | PoSA | Centralized, many users, fast transactions | Beginner entry, Degen |
| Polygon | PoS (Ethereum sidechain) | Expands ETH performance | DeFi, small payments |
| Arbitrum | Optimistic Rollup | L2 for ETH, low fees | DeFi airdrop hotspot |
| zkSync | ZK Rollup | Strong privacy, cutting-edge ZK technology | Emerging ecosystem |
Web3 can be understood as a world of "multiple chains coexisting," where each chain is like a country with its own systems, languages, and habits.
What are Layer 1 and Layer 2?#
It is essentially the "layered structure of the blockchain world."
Layer 1: The Main Chain Itself#
The bottom layer of the chain, responsible for processing all transactions and consensus. Like the main roads of a city, Bitcoin, Ethereum, and Solana are all L1.
Characteristics: secure but congested (expensive + slow)
Layer 2: The Main Chain's External Accelerator#
What if the main chain is too slow? Move some transactions "out to process," only syncing the results back.
L2 is such a layer of "external high-speed channels," with two common methods:
- Optimistic Rollup: Assume no one cheats first, only verify when someone reports (Representative: Arbitrum)
- ZK Rollup: Generate a mathematical proof for each transaction (Representative: zkSync)
This way, you can "enjoy Ethereum's security" while reducing costs + increasing speed.
Bonus: Layer 0 (Underlying Communication Protocol)#
Sometimes we also hear about Layer 0, such as Polkadot and Cosmos. These projects provide a protocol for "enabling communication between different chains," solving cross-chain issues.
They are not chains but "bridges between chains."