Blockchain Implementation in C

This project demonstrates a basic blockchain implementation in C, showcasing core blockchain features and advanced functionalities like Proof of Work, serialization, and networking. It is designed to highlight your expertise in low-level programming, cryptography, and systems design.

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Features

1. Core Features

   • Add and validate blocks.
   • SHA-256-based cryptographic hashing for data integrity.
   • Verify the validity of the blockchain.

2. Advanced Features

   • Proof of Work (PoW): Mine blocks by solving a computational puzzle.
   • Serialization: Save and load the blockchain to/from a file for persistence.
   • Networking: Send and receive blockchain data between peers over a network.

3. Scalability

   • Modular design for adding additional blockchain features, e.g., transactions or Merkle Trees.

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Project Structure

blockchain/
├── blockchain.h      # Header file defining blockchain structure and functions
├── blockchain.c      # Core blockchain implementation
├── block.c           # Block-specific implementation
├── hash.c            # SHA-256 hashing functions
├── network.c         # Networking utilities for peer-to-peer communication
├── Makefile          # Build system to compile the project
├── test/             # Directory for test cases
├── blockchain.dat    # Serialized blockchain file (generated after running tests)
└── README.md         # Project documentation

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Getting Started

Prerequisites

• A C compiler, e.g., gcc.
• make build tool.
• Basic knowledge of C programming and blockchain concepts.

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Installation

1. Clone this repository:

   git clone https://github.com/tobidelly/blockchain_project.git
   cd blockchain_project

2. Compile the project:

   make

3. Run the tests to verify functionality:

   ./blockchain

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Usage

1. Proof of Work

Mine a block by solving a computational puzzle:

./blockchain

Output example:

Mined Block:
Index: 1
Hash: 00001a3f89dc9c6e8ec5a70c132...
Nonce: 45123

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2. Serialization

Save the blockchain to a file:

./blockchain

Load the blockchain from the file and print its contents:

cat blockchain.dat

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3. Networking

Run the server to accept blockchain data:

./blockchain_server

Send the blockchain to a peer:

./blockchain_client

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How It Works

Core Blockchain

• Each block contains:
  • Index
  • Timestamp
  • Data
  • Previous block hash
  • Current block hash
  • Nonce (for Proof of Work)
• Hashing ensures the immutability of the blockchain.

Proof of Work

• The block is mined by finding a nonce such that the hash meets a predefined difficulty.

Serialization

• The blockchain is serialized into a binary file for persistence.
• It can be reloaded to reconstruct the blockchain in memory.

Networking

• The server listens for connections from peers.
• Clients send serialized blockchain data to peers.

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Future Enhancements

• Add support for transactions and wallets.
• Implement Merkle Trees for efficient block data validation.
• Enhance networking with peer discovery and distributed consensus.
• Optimize Proof of Work for variable difficulty levels.

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Author

Tobi Delly

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License

This project is licensed under the MIT License. See the LICENSE file for details.

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Acknowledgments

• Cryptographic Hashing: Inspired by the SHA-256 algorithm.
• Networking: Concepts from peer-to-peer communication systems.
• Blockchain Basics: Referenced from Bitcoin and Ethereum whitepapers.