BlockVerify 🔗

Blockchain-based File Integrity Verification System SHA-256 · Proof-of-Work · IPFS via Pinata · Multi-user Authentication · MetaMask Wallet Login

Built by Subham Mishra B.Tech CSE (AI/ML) — Centurion University of Technology and Management

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What is BlockVerify?

BlockVerify lets you register any file (image, document, ML model) into a blockchain. Each file is hashed with SHA-256, mined into a block using Proof-of-Work, and stored on IPFS via Pinata. Anyone can later verify whether a file has been tampered with by checking its hash against the chain.

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Features

• 🔐 Multi-user login & signup — anyone can create an account
• 🦊 MetaMask wallet login — Sign-In with Ethereum on Sepolia Testnet
• 👤 Per-user file registry — each user sees only their own files
• ⛏ Proof-of-Work mining — difficulty 4 (hash must start with 0000)
• 🔒 SHA-256 hashing — content-based, not filename-based
• 🌐 IPFS storage via Pinata — decentralized blockchain persistence
• ⬇ File download — download your registered files anytime
• 🗑 File deletion — remove files from your account
• 🛡 Admin panel — separate admin login with full user management
• 📊 Chain explorer — view all blocks with validity check

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Project Structure

blockchain_iris_project/
│
├── app.py                  ← Flask routes only
├── blockchain.py           ← Block + Blockchain classes with PoW
├── hash_utils.py           ← SHA-256 hashing + file type detection
├── pinata_utils.py         ← Pinata IPFS integration
├── train_model.py          ← Iris model trainer
├── iris_model.joblib       ← Trained ML model
├── requirements.txt        ← Python dependencies
├── .env                    ← API keys (never commit this)
├── templates/
│   ├── index.html          ← Main app HTML
│   └── admin.html          ← Admin panel HTML
├── static/
│   ├── css/
│   │   ├── main.css        ← Main app styles
│   │   └── admin.css       ← Admin styles
│   └── js/
│       ├── main.js         ← Main app JavaScript
│       └── admin.js        ← Admin JavaScript
├── users.json              ← Auto-created on first signup
├── uploaded_files/         ← Auto-created file storage
└── README.md

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Setup & Installation

1. Clone the repo

git clone https://github.com/subham23s/BLOCK-VERIFIER.git
cd BLOCK-VERIFIER

2. Create virtual environment

python -m venv venv
venv\Scripts\activate        # Windows
source venv/bin/activate     # Linux/Mac

3. Install dependencies

pip install -r requirements.txt

4. Set up Pinata IPFS

1. Create a free account at pinata.cloud
2. Go to API Keys → Generate new key
3. Copy your API Key and Secret Key

5. Create .env file

PINATA_API_KEY=your_pinata_api_key_here
PINATA_SECRET_KEY=your_pinata_secret_key_here
ADMIN_USERNAME=your_admin_username
ADMIN_PASSWORD=your_admin_password

6. Run the app

python app.py

Browser opens automatically at http://127.0.0.1:5000

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Usage

Regular Users

1. Open http://127.0.0.1:5000
2. Sign Up with username and password — or connect MetaMask wallet
3. Register tab — drop any file to register it on the blockchain
4. Verify tab — drop a file to check if it has been tampered with
5. My Files tab — view, download, or delete your registered files
6. Chain tab — explore all blocks in the blockchain

MetaMask Wallet Login

1. Click Connect MetaMask Wallet on the login page
2. MetaMask auto-switches to Sepolia Testnet
3. Sign the challenge message (no ETH spent)
4. First time — choose a display name
5. Returning — logs in instantly

Admin

Login from the main page with admin credentials set in .env — automatically redirects to the admin panel at /admin.

Admin can:

• View all registered users and their files
• Delete user accounts
• Update Pinata API keys
• Change admin password

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How It Works

File Upload
    ↓
SHA-256 Hash (content-based fingerprint)
    ↓
Proof-of-Work Mining (find nonce so hash starts with "0000")
    ↓
Block added to Blockchain
    ↓
Chain saved to IPFS via Pinata (get CID)
    ↓
File stored in uploaded_files/<hash>/
    ↓
User's file list updated in users.json

Verification

Upload file
    ↓
Compute SHA-256 hash
    ↓
Search blockchain for matching hash
    ↓
✅ Found = File is intact
❌ Not found = File tampered or not registered

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User Data Storage

User accounts (username, hashed password, file list) are stored locally in users.json. This is ideal for college demos and small deployments. For large-scale public deployment, this can be migrated to Firebase Firestore.

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Tech Stack

Layer	Technology
Backend	Python, Flask
Blockchain	Custom implementation (SHA-256 + PoW)
Storage	IPFS via Pinata
Frontend	HTML, CSS, Vanilla JS
Auth	Flask Sessions + SHA-256 + MetaMask SIWE
User Store	Local JSON file
ML Model	Scikit-learn (Iris dataset)

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API Endpoints

Method	Endpoint	Description
POST	/signup	Create new account
POST	/login	Login (redirects admin to /admin)
POST	/logout	Logout and clear session
POST	/wallet/challenge	Get challenge for MetaMask signing
POST	/wallet/verify	Verify wallet signature
POST	/wallet/register	Register new wallet user
POST	/register	Register a file on blockchain
POST	/verify	Verify file integrity
GET	/my_files	Get logged-in user's files
GET	/download/<hash>	Download a registered file
POST	/delete_file	Remove file from account
GET	/chain	Get full blockchain data
GET	/pinata_status	Check Pinata connection
GET	/admin	Admin panel
GET	/admin/users	Get all users (admin only)
POST	/admin/config	Update Pinata keys (admin only)

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.gitignore

venv/
.env
users.json
uploaded_files/
firebase_key.json
__pycache__/
*.joblib
latest_cid.txt

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License

MIT License — © 2025 Subham Mishra