Interactive Proof-of-Work Blockchain in C++

Overview

This is a comprehensive, interactive implementation of a basic blockchain using C++ and a proof-of-work mining mechanism. The project demonstrates core blockchain concepts including block creation, cryptographic hashing, mining, and chain validation.

Features

• Interactive command-line blockchain interface
• Proof-of-work mining algorithm
• Dynamic block creation
• Blockchain validity verification
• Adjustable mining difficulty
• SHA256 cryptographic hashing using OpenSSL

Project Structure

proof-of-work-blockchain-cpp/
│
├── CMakeLists.txt        # Build configuration
├── README.md             # Project documentation
│
├── src/                  # Source code
│   ├── main.cpp          # Main application
│   ├── block.cpp         # Block implementation
│   ├── block.h           # Block class definition
│   ├── blockchain.cpp    # Blockchain implementation
│   └── blockchain.h      # Blockchain class definition
│
└── include/              # Header files
    └── sha256.h          # Cryptographic hashing utility

Prerequisites

• C++17 compatible compiler
• CMake (version 3.10 or higher)
• OpenSSL development libraries

Setup Guide

Linux

Installation Dependencies

sudo apt update
sudo apt install cmake libssl-dev build-essential

Building the Project

# Create build directory
mkdir build
cd build

# Generate build files
cmake ..

# Build the project
cmake --build .

Usage

After building, run the blockchain executable

./blockchain

Core Components

• Block: Represents individual blocks in the chain

  • Contains index, timestamp, data, hash, and previous hash
  • Implements proof-of-work mining

• Blockchain: Manages the entire chain of blocks

  • Creates genesis block
  • Adds new blocks
  • Validates blockchain integrity

• SHA256: Cryptographic hashing utility

  • Uses OpenSSL's EVP interface
  • Generates unique hash for block data

Proof-of-Work Mining

The mining process involves finding a hash that starts with a specific number of zeros, determined by the difficulty level. This requires computational work, simulating the mining process in cryptocurrencies.

Interactive Menu Options

• Add Block

  • Enter custom data for a new block
  • Automatically mines the block with the current difficulty

• Check Blockchain Validity

  • Verifies the integrity of the entire blockchain
  • Checks hash connections between blocks

• View Blockchain Details

  • Displays information for each block
  • Shows block index, current hash, and previous hash

• Change Mining Difficulty

  • Dynamically adjust proof-of-work complexity
  • Higher difficulty increases mining time and computational requirements

• Exit

  • Terminate the blockchain application

Customization

• Adjust mining difficulty in the main application
• Modify block data structure
• Extend hashing or validation logic