Bitcoin Consensus Implementation

This project is a simplified implementation of Bitcoin's consensus mechanism using TypeScript. It simulates Proof of Work (PoW) algorithm, blockchain structure, and mining processes.

🚀 Features

• Blockchain Structure: Linked block chain implementation
• Proof of Work: SHA-256 based mining algorithm
• Multi-Miner Support: Parallel mining simulation
• Race Condition Protection: Thread-safe mining implementation
• Dynamic Difficulty: Adjustable mining difficulty
• Reward System: Mining reward system with halving mechanism

📁 Project Structure

src/
├── block.ts       # Block class and structure
├── blockchain.ts  # Blockchain logic and validation
├── crypto.ts      # SHA-256 hash functions
├── miner.ts       # Mining algorithm and miner class
├── index.ts       # Main execution file
└── worker.ts      # Worker thread implementation

🛠️ Installation

Requirements

• Node.js (v18 or higher)
• npm or yarn

Install Dependencies

npm install

Compile TypeScript and Run

npm run build

OR

npx tsc && node src/index.js

🔧 Usage

Simple Mining Example

import { Block } from "./block";
import { Blockchain } from "./blockchain";
import { Miner } from "./miner";

// Create blockchain (difficulty: 4)
const blockchain = new Blockchain(4);

// Create miner
const miner = new Miner("Alice");

// Create new block
const newBlock = new Block(
    "Transaction Data",
    blockchain.getLatestBlock().hash,
    blockchain.length() + 1
);

// Start mining process
const success = miner.mine(
    newBlock,
    blockchain.getLatestBlock().hash,
    blockchain
);

if (success) {
    console.log("Block added successfully!");
    console.log(`Miner balance: ${miner.currValue}`);
}

🏗️ Core Classes

Block

class Block {
    nonce: number; // Mining nonce value
    blockNumber: number; // Block sequence number
    data: string; // Block data
    hash: string; // Block hash
    fingerprint: string; // Previous block hash
}

Blockchain

class Blockchain {
    chain: Array<Block>; // Block chain
    difficulty: number; // Mining difficulty
    rewardPrice: number; // Mining reward

    addBlock(hash: string, newBlock: Block, miner: Miner): boolean;
    validateNewBlock(hash: string): boolean;
}

Miner

class Miner {
    name: string; // Miner name
    publicKey: string; // Public key
    privateKey: string; // Private key
    currValue: number; // Current balance

    mine(block: Block, previousHash: string, blockchain: Blockchain): boolean;
}

⚡ Mining Algorithm

The mining process follows these steps:

1. Target Calculation: Target value is determined based on difficulty
2. Nonce Search: Search for nonce from random starting point
3. Hash Calculation: SHA-256(previousHash + nonce + timestamp + minerName)
4. Validation: Check if hash < target
5. Block Addition: Attempt to add block to blockchain when valid hash is found

Race Condition Protection

To prevent finding the same nonce in multi-threading environment:

// Uniqueness ensured with timestamp and miner name
hash = hashString(previousHash + seed + timestamp + this.name);

🎯 Difficulty System

Difficulty determines how many leading zeros the hash must have:

• Difficulty 1: 0xxxxxxx... (1 zero)
• Difficulty 4: 0000xxxx... (4 zeros)
• Difficulty 6: 000000xx... (6 zeros)

Mining time increases exponentially as difficulty increases.

💰 Reward System

• 10 coins reward for each successful mining
• Halving occurs every 100 blocks
• Only the first miner to find solution gets rewarded

🔄 Blockchain Validation

Each new block must pass these validations:

1. Hash Validation: Does hash comply with difficulty rules?
2. Block Number: Is it sequential? (previous + 1)
3. Fingerprint: Is previous block's hash correct?
4. Uniqueness: Has block already been added?

🐛 Known Limitations

• Simplified Merkle Tree: No transaction tree like real Bitcoin
• Network Simulation: No P2P network simulation
• UTXO Model: No transaction input/output model
• Script System: No Bitcoin script support

🤝 Contributing

1. Fork the project
2. Create feature branch (git checkout -b feature/amazing-feature)
3. Commit changes (git commit -m 'Add amazing feature')
4. Push to branch (git push origin feature/amazing-feature)
5. Open Pull Request

⏩ To-do

• Frontend might be created to see the system clearly

🔗 Resources

• Bitcoin Whitepaper
• Proof of Work Explained
• SHA-256 Algorithm

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Note: This project is for educational purposes and is not suitable for production use.