🗳️ Blockchain-Based Voting System

A secure, transparent, and tamper-proof electronic voting system built using blockchain technology. This project demonstrates how cryptographic principles and decentralized infrastructure can ensure vote integrity and public trust.

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📌 Project Overview

This application leverages blockchain, SHA-256 hashing, digital signatures, and proof-of-work to build a robust and secure voting platform. It features a Flask-based web interface for voters to cast votes, view blockchain data, mine new blocks, and validate the system.

🎯 Objectives

• Ensure vote integrity through cryptographic signatures and immutability.
• Increase voter trust by providing a transparent and verifiable voting process.
• Prevent vote tampering via decentralized consensus and proof-of-work.

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🚀 Features

• 🔐 Secure Voting: All votes are digitally signed using private keys and stored immutably on the blockchain.
• 🌐 Decentralization: No central authority—data is stored in a distributed and tamper-proof ledger.
• 🧾 Auditability: Full blockchain ledger can be viewed and verified at any time.
• ⚡ Real-Time Results: Votes are counted instantly after block mining.
• 🔍 Blockchain Validation: Every block is verified using hash, proof-of-work, and signature integrity checks.

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🛠️ Technologies Used

• Python 3
• Flask – Web application framework
• PyCryptodome / cryptography – For key generation and digital signatures
• SHA-256 – For hashing and linking blocks
• HTML/CSS – Frontend templates

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🔄 Workflow

1. User accesses the voting interface and submits a vote.
2. The vote is digitally signed using a private key.
3. The vote is added to pending transactions.
4. A new block is mined using proof-of-work.
5. Mined blocks are added to the blockchain.
6. The blockchain can be validated at any time.
7. Real-time results can be viewed based on mined votes.

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📋 Routes and Endpoints

Route	Method	Description
/	GET	Homepage with navigation
/vote	POST	Submit a new vote (voter_id, candidate_id)
/mine	GET	Mine pending transactions into a block
/chain	GET	View the entire blockchain
/results	GET	View current voting results
/validate	GET	Validate blockchain integrity
/public_key	GET	View system's public key for signature verification

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🔐 Cryptographic Components

🔗 Hashing (SHA-256)

• Ensures immutability and integrity of blocks.
• Each block’s hash depends on its data and the previous block’s hash.

✍️ Digital Signatures

• Votes are signed using the voter's private key.
• Signatures are verified using the public key to ensure authenticity.

⛏️ Proof of Work

• Prevents tampering by adding computational cost.
• New proof must satisfy: hash(new_proof^2 - previous_proof^2) starting with "0000".

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👩‍💻 Code Structure

📁 interface.py

• Handles the web interface using Flask.
• Routes for voting, mining, chain viewing, and result display.

📁 blockchain.py

• Manages blockchain operations:
  • create_block
  • add_vote
  • proof_of_work
  • is_chain_valid
  • validate_votes

📁 crypto_utils.py

• Implements:
  • sign_vote
  • verify_vote
  • hash_block
  • get_public_key_pem

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📄 License

This project is for educational and demonstration purposes. Not intended for production use without security review.

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📬 Contact

For questions, feel free to reach out via GitHub or during the course showcase.