Java Blockchain Implementation 🔗

A simple yet functional blockchain implementation in Java that demonstrates the core concepts of blockchain technology.

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🌟 Overview

This blockchain implementation showcases the fundamental workings of cryptocurrency transactions and blockchain technology. The project includes essential features such as:

• Block creation and mining
• Transaction processing with digital signatures
• Proof-of-work consensus mechanism
• Wallet balance tracking
• Chain validation
• Cryptographic security features

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🧱 Key Components

Blocks

Each block in the chain contains:

• Transactions
• Timestamp
• Hash of the previous block
• Hash of the current block
• Nonce (used in mining)
• Merkle root (for transaction verification)

Transactions

Transactions include:

• Sender and recipient public keys
• Amount being transferred
• Digital signature for authenticity
• Transaction ID

Mining

• Uses SHA-256 proof-of-work algorithm
• Adjustable mining difficulty
• Mining rewards for block creators

Security Features

• Public/private key cryptography for secure transactions
• Digital signatures for transaction verification
• SHA-256 hashing for block integrity
• Merkle trees for efficient transaction verification

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💻 Example Usage

// Initialize the blockchain
Blockchain blockchain = new Blockchain();

// Generate wallets (key pairs)
KeyPair aliceWallet = CryptoUtil.generateKeyPair();
KeyPair bobWallet = CryptoUtil.generateKeyPair();
KeyPair minerWallet = CryptoUtil.generateKeyPair();

// Create and sign a transaction
Transaction transaction = new Transaction(aliceWallet.getPublic(), bobWallet.getPublic(), 50.0);
transaction.generateSignature(aliceWallet.getPrivate());

// Add the transaction to the blockchain and mine pending transactions
blockchain.addTransaction(transaction);
blockchain.minePendingTransactions(minerWallet.getPublic());

// Display blockchain data
System.out.println(blockchain);