Blockchain Fundamentals
Blockchain technology is changing the world. This article systematically introduces core blockchain concepts.
What is Blockchain?
Blockchain is a distributed database technology that uses cryptographic methods to "link" data "blocks" in chronological order, forming an immutable data chain.
Core Concepts
1. Distributed Ledger
Blockchain is a decentralized ledger jointly maintained by all participating nodes, with no single controlling party.
Characteristics:
- Data distributed across multiple nodes
- All nodes maintain consistent data
- No centralized institution required
2. Block Structure
Each block contains:
- Block Header: Contains previous block hash, timestamp, difficulty value, etc.
- Block Body: Contains transaction data
- Hash Value: Unique identifier of the block
3. Consensus Mechanism
How do nodes in the network reach agreement on data state?
Mainstream Consensus Mechanisms:
- PoW (Proof of Work): Used by Bitcoin, through computing power competition
- PoS (Proof of Stake): Used by Ethereum 2.0, through token staking
- DPoS (Delegated Proof of Stake): Used by EOS, voting to elect validators
- PBFT (Practical Byzantine Fault Tolerance): Commonly used in consortium blockchains
4. Hash Functions
Hash functions convert data of any length into fixed-length strings.
Properties:
- One-way: Cannot reverse engineer original data from hash
- Deterministic: Same input produces same output
- Avalanche effect: Tiny input changes cause massive output changes
5. Asymmetric Encryption
Uses public and private key pairs for encryption and signing.
Applications:
- Public Key: Generate wallet address, receive assets
- Private Key: Sign transactions, prove ownership
6. Merkle Tree
A hash tree structure for efficiently verifying large amounts of data.
Advantages:
- Fast data integrity verification
- Saves storage space
