basic-blockchain-implementation

Simple Blockchain in JavaScript

This is a simple blockchain implementation in JavaScript using Node.js and the built-in crypto module. The project demonstrates the fundamental concepts of blockchain, including block creation, proof-of-work, and chain validation.

Features

• Block structure with SHA-256 hashing
• Proof-of-Work (PoW) mechanism for mining
• Genesis block creation
• Adding new blocks to the chain
• Blockchain integrity validation
• Demonstrates tampering detection

Prerequisites

Ensure you have Node.js installed on your system. You can check by running:

node -v

Installation

Clone the repository and navigate to the project folder:

git clone https://github.com/your-repo/blockchain-js.git
cd blockchain-js

Usage

Run the blockchain script using Node.js:

node blockchain.js

Code Overview

Block Class

Defines a block with an index, timestamp, transactions, previous hash, nonce, and hash. The calculateHash method generates a SHA-256 hash, and mineBlock performs proof-of-work.

Blockchain Class

Manages the blockchain, including:

• Genesis block creation
• Adding new blocks
• Validating the blockchain integrity

Example Usage

The script initializes a blockchain, mines two blocks, and validates the chain. It also demonstrates blockchain tampering detection.

Expected Output

Mining Block 1...
Block mined: <hash>
Mining Block 2...
Block mined: <hash>
Blockchain: {...}
Is blockchain valid? true
Is blockchain valid after tampering? false

License

This project is licensed under the MIT License.

Author

Deepesh Singh Rathore