Simple Blockchain Project

Overview

This project is a simple blockchain implementation featuring basic functionalities such as signing transactions, creating transactions, a robust UI, transaction fees, block rewards for miners, consensus across all nodes, simple UTXO management, and a maximum coin supply of 21 million. The project includes both a frontend (user interface) and a backend.

Features

• Robust UI
• Sign and Create transactions
• Transaction fee
• Block reward for miners
• Consensus among all nodes
• Simple UTXO management
• Maximum coin supply of 21 million
• get_block_subsidy function similar to Bitcoin

Frontend

The frontend is built using Flask, HTML, CSS, and JavaScript. It includes the following pages:

Home page

• Sign and create transactions
• View chain of blocks
• View peers
• Generate wallet on the home page
• Connect to random blockchain nodes (user can choose node IP)

Block page

Mempool Page

Backend

The backend is structured as follows:

• app directory: Contains necessary APIs with Flask.
• run.py: Main program that restores seed node data and registers new nodes with seed nodes. It also runs two threads: one for the mining loop and one for consensus with new peers.
• node_config.py: Configuration file for node settings.
• core directory: Contains classes for blockchain, block, transaction, consensus, config and UTXO management.
• consensus.py: Functions for consensus and announcing blocks, transactions, and peers.
• config.py: Configuration file for blockchain settings.

Getting Started

Prerequisites

• Docker
• Docker Compose

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/simple-blockchain.git
   cd simple-blockchain

2. Build and run the project using Docker Compose:

   make rebuild-up

Configuration

The backend node config is set in compose.yaml (key: default):

SEED_NODE: http://127.0.0.1:8000 # Seed node that help new nodes to register
NODE_IP: 127.0.0.1 # Current node ip
NODE_PORT: 8000 # Current node port
chain_file_name: ./data/chain_bkp.json # File path to store backup of seed node
COINBASE_BENEFICIARY: 1ad4154a06f1126a504737f501fd05e1e76eecd9538ae1f497ca31144e9ec96aa59d4fe155888a07af75321ad45309596fd8dd48ef59414bb134968b6b0d7f42

The backend core config is set in baackend/core/config.py (key: default):

DIFFICULTY = 4 # Difiiculty of PoW algorithm
FEE_PER_TRANSACTION = 0.01  # 0.01% of amount

Usage

Access the frontend at http://localhost:5000. The following pages are available:

• Home: Sign and create transactions, view chain of blocks, view peers, generate wallet.
• Block: View block details.
• Mempool: View mempool.

Development

Build the frontend and backend separately:

make build-frontend
make build-backend

Start the services:

make up

Stop the services:

make down

Restart the services:

make restart

Down/Rebuild/Up the services:

make rebuild-up

ToDo:

• Bitcoin-like UTXO
• Propagate tx in frontend