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Simple Blockchain Network

A minimal blockchain network implementation in Python. This project demonstrates the core concepts of blockchain, including blocks, mining, proof of work, and node-to-node communication using a simple REST API.

Table of Contents

• About the Project
• Features
• Technologies
• Getting Started
  • Prerequisites
  • Installation
  • Dockerization
• Usage
  • Starting and Registering Nodes
  • Endpoints
  • Testing and Verification
• Future Improvements

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About the Project

This project is a Python-based blockchain network where nodes communicate over a REST API. The blockchain supports basic functionalities like transaction handling, mining with proof-of-work, and peer-to-peer communication, making it an excellent way to understand blockchain infrastructure.

Features

• Blockchain Structure: Manages a chain of blocks, each containing transactions.
• Proof of Work (PoW): Implements a mining mechanism that adds computational difficulty to secure the network.
• REST API Node Communication: Exposes endpoints to interact with nodes (e.g., mining, adding transactions).
• Peer-to-Peer Networking: Allows nodes to connect and share information with other nodes in the network.
• Dockerized Node Setup: Easily simulate a multi-node blockchain network using Docker.

Technologies

• Python 3.9+
• Flask: For creating RESTful API endpoints.
• Hashlib: Used to secure block hashes.
• Docker: For containerizing nodes and simulating a networked environment.

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Getting Started

Prerequisites

• Python 3.9+: Ensure you have Python installed on your system.
• Docker: Install Docker to containerize and manage multiple nodes.

Installation

1. Clone the repository:

   git clone https://github.com/federico2102/SimpleBlockchainNetwork.git

2. Navigate to the project directory:

   cd SimpleBlockchainNetwork

3. Install dependencies:

   pip install -r requirements.txt

Dockerization

To simulate a multi-node network, Dockerize each node and connect them within a Docker network.

1. Create a Docker Network:

   docker network create blockchain-network

2. Build the Docker Image:

   docker build -t blockchain-node .

3. Run Containers for Each Node:

   docker run -d --name node1 --network blockchain-network -p 5000:5000 blockchain-node
   docker run -d --name node2 --network blockchain-network -p 5001:5000 blockchain-node
   docker run -d --name node3 --network blockchain-network -p 5002:5000 blockchain-node

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Usage

Starting and Registering Nodes

After starting nodes as Docker containers, register each node with others to enable peer-to-peer communication.

1. Register node2 with node1:

   Invoke-WebRequest -Uri http://localhost:5000/nodes/register -Method POST -Body '{"nodes": ["http://node2:5000"]}' -ContentType "application/json"

2. Register node3 with node1:

   Invoke-WebRequest -Uri http://localhost:5000/nodes/register -Method POST -Body '{"nodes": ["http://node3:5000"]}' -ContentType "application/json"

Endpoints

• Mine a Block

  • URL: http://localhost:5000/mine
  • Method: GET
  • Description: Mines a new block with pending transactions and adds it to the blockchain.
  • Example:

    Invoke-WebRequest -Uri http://localhost:5000/mine -Method GET

• View the Full Blockchain

  • URL: http://localhost:5000/chain
  • Method: GET
  • Description: Returns the entire blockchain in JSON format.
  • Example:

    Invoke-WebRequest -Uri http://localhost:5000/chain -Method GET

• Add a New Transaction

  • URL: http://localhost:5000/transactions/new
  • Method: POST
  • Description: Adds a new transaction to the list of pending transactions.
  • Data Format:

    {
      "sender": "A",
      "receiver": "B",
      "amount": 50
    }

  • Example:

    Invoke-WebRequest -Uri http://localhost:5000/transactions/new -Method POST -Body '{"sender": "A", "receiver": "B", "amount": 50}' -ContentType "application/json"

• Register a Node

  • URL: http://localhost:5000/nodes/register
  • Method: POST
  • Description: Register a list of peer nodes to enable decentralized communication.
  • Data Format:

    {
      "nodes": ["http://localhost:5001", "http://localhost:5002"]
    }

Testing and Verification

1. Confirm Node Registration:

   • Retrieve the list of registered peers from node1:

     Invoke-WebRequest -Uri http://localhost:5000/nodes -Method GET

2. Add and Mine Transactions:

   • Add a transaction to node1:

     Invoke-WebRequest -Uri http://localhost:5000/transactions/new -Method POST -Body '{"sender": "Alice", "receiver": "Bob", "amount": 25}' -ContentType "application/json"

   • Mine a block on node1 to add the transaction to the blockchain:

     Invoke-WebRequest -Uri http://localhost:5000/mine -Method GET

3. Verify Blockchain Synchronization:

   • Retrieve the blockchain from each node to verify they are synchronized:

     Invoke-WebRequest -Uri http://localhost:5000/chain -Method GET
     Invoke-WebRequest -Uri http://localhost:5001/chain -Method GET
     Invoke-WebRequest -Uri http://localhost:5002/chain -Method GET

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Future Improvements

Some possible expansions to this project include:

• Consensus Algorithm: Implement a consensus protocol to synchronize the longest chain across nodes.
• Web Interface: Add a user-friendly front-end for easier interaction with the blockchain.
• Enhanced Peer Discovery: Develop automated peer discovery and dynamic connection handling.
• Improved Security: Use SSL/TLS for secure communication between nodes.

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