🧱 Blockchain Simulation in Python

This project simulates a simplified blockchain system using Python and Streamlit. It includes the main components of a blockchain: users with wallets, transactions, UTXO handling, mining with Proof of Work (PoW), block creation, and an interactive interface.

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🚀 Implemented Features

💳 Wallets and Keys

• Each user has a private/public key pair (ECDSA over secp256k1).
• The address is generated as the SHA-256 hash of the public key.

📤 Transactions and UTXO

• UTXO-based model to track balances and transfers.
• Digital signatures to authorize transactions.
• Support for mining fees.

🔗 Blocks and Blockchain

• Each block contains valid transactions, the previous hash, timestamp, and nonce.

⛏️ Genesis Block and Mining

• The genesis block delivers 1000 coins to the first user.
• Simplified proof of work: the hash must start with a certain number of zeros.
• Block rewards + fees are granted to the miner through a coinbase transaction.

💻 Streamlit Interface

• Create a new system or load an existing one
• View system summary
• Create new wallets
• Send transactions
• Mine blocks
• Visualize the blockchain
• View user balances
• Save the system

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📂 Project Structure

README.md
└── src
    ├── Block.py                     # Block definition and hashing
    ├── BlockchainSimulation.py      # Streamlit interface logic
    ├── System.py                    # System controller (users, transactions, mining)
    ├── Transaction.py               # Transaction logic, signatures, and validation
    ├── UTXO.py                      # Unspent Transaction Output (UTXO) model
    └── User.py                      # Wallet and key management

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📚 Technologies Used

• Python 3.11
• Streamlit
• ECDSA (Elliptic Curve Cryptography)
• SHA-256 hashing
• Pandas (for data visualization)

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🎥 System Demo

Click here to watch the demo video