Blockchain Introduction.
This tutorial introduces blockchain technology, its components, how it works, and real-world use cases.
1. What is Blockchain?
Blockchain is a decentralized and distributed digital ledger that records transactions securely across multiple computers.
- Decentralized
- Transparent
- Immutable
- Secure
2. How Blockchain Works
- A transaction is created
- Transaction is broadcast to the network
- Nodes validate the transaction
- Transaction is added to a block
- Block is added to the blockchain
3. Blocks and Hashing
Each block contains:
- Transaction data
- Timestamp
- Previous block hash
- Current block hash
Block Hash = SHA256(Data + Previous Hash + Timestamp)4. Types of Blockchain
- Public – Bitcoin, Ethereum
- Private – Enterprise blockchains
- Consortium – Controlled by organizations
- Hybrid – Combination of public and private
5. Consensus Mechanisms
Consensus ensures agreement across the network.
- Proof of Work (PoW)
- Proof of Stake (PoS)
- Delegated Proof of Stake (DPoS)
- Proof of Authority (PoA)
6. Cryptocurrencies
Cryptocurrencies are digital currencies built on blockchain.
- Bitcoin – First cryptocurrency
- Ethereum – Smart contract platform
- Altcoins – Alternative coins
7. Smart Contracts
Smart contracts are self-executing programs stored on the blockchain.
// Example (Solidity)
contract Hello {
function greet() public pure returns (string memory) {
return "Hello Blockchain";
}
}
Smart contracts remove intermediaries and reduce costs.
8. Blockchain Security
- Cryptographic hashing
- Decentralization
- Public-private key encryption
- Immutability
Smart contract bugs can lead to financial losses.
9. Blockchain Use Cases
- Cryptocurrency & payments
- Supply chain management
- Healthcare records
- Voting systems
- NFTs & digital ownership
10. Advantages & Limitations
Advantages
- High transparency
- Improved security
- Reduced fraud
Limitations
- Scalability issues
- High energy consumption
- Regulatory uncertainty
11. Career Paths in Blockchain
- Blockchain Developer
- Smart Contract Engineer
- Blockchain Architect
- Web3 Developer
- Blockchain Security Analyst
12. Conclusion
Blockchain is transforming industries by enabling trustless, decentralized systems. Learning blockchain opens doors to Web3 and emerging technologies.