🔐 Profile Lock - Chrome Extension

A Chrome extension that locks your browser profile with a password for privacy protection. Perfect for freelancers who use separate Chrome profiles for different clients, or anyone who shares a computer and wants to protect their browsing data.

Features

• 🔐 Password Protection: Lock your Chrome profile with a secure password
• 🚀 Auto-lock on Startup: Profile is automatically locked when Chrome starts
• ⏰ Idle Auto-lock: Optionally lock after 5 minutes of inactivity
• 🎨 Clean UI: Modern, non-intrusive lock screen overlay
• 🔄 Easy Management: Change or remove password anytime

📋 Requirements

• Google Chrome (or Chromium-based browser) version 88 or higher
• Chrome Extensions API support (Manifest V3)

🚀 Installation

Method 1: Install from GitHub (Recommended)

1. Download the extension:

   git clone https://github.com/arzumy/chrome-profile-lock.git
   cd chrome-profile-lock

   Or download as ZIP from the repository and extract it.

2. Load in Chrome:

   • Open Chrome and navigate to chrome://extensions/
   • Enable Developer mode (toggle in the top right)
   • Click Load unpacked
   • Select the chrome-profile-lock folder
   • The extension icon will appear in your toolbar

3. Restart Chrome to ensure the extension loads properly

Method 2: Pack as .crx (for distribution)

1. Go to chrome://extensions/
2. Enable Developer mode
3. Click Pack extension
4. Select the chrome-profile-lock folder
5. This creates a .crx file you can share
6. Restart the browser after installation

Usage

First Time Setup

1. Click the lock icon in your Chrome toolbar
2. Enter a password (minimum 4 characters)
3. Confirm the password
4. Optionally enable auto-lock when idle
5. Click "Set Password"

Locking Your Profile

• Manual: Click the extension icon → "Lock Now"
• Automatic: Profile locks when Chrome starts
• Idle: If enabled, locks after 5 minutes of inactivity

Unlocking

When locked, a full-screen overlay appears. Enter your password to unlock.

Managing Your Password

Click the extension icon when unlocked to:

• Lock Now: Immediately lock the profile
• Change Password: Update your password
• Remove Password: Disable the lock feature

Security Notes

⚠️ Important Limitations:

1. This extension provides a deterrent, not absolute security
2. A determined user could:
   • Disable the extension via chrome://extensions/
   • Access Chrome's profile folder directly on disk
   • Use Chrome's Task Manager to close extension processes

For Maximum Security, Also Consider:

• Using separate OS user accounts (strongest option)
• Enabling full-disk encryption (BitLocker/FileVault)
• Always locking your computer when away
• Using a password manager for sensitive accounts

🛠️ How It Works

1. Password Storage: Password is hashed using SHA-256 before storage
2. Local Storage: Hash is stored in Chrome's local storage (per-profile, never synced)
3. Content Script: Injects a lock overlay on all pages when locked
4. Background Service Worker: Manages lock state and idle detection
5. Messaging API: Communication between components via Chrome's messaging API

Technical Details

• Manifest Version: 3 (MV3)
• Permissions: storage, tabs, idle
• Content Scripts: Runs on all URLs (<all_urls>) at document start
• Storage: Uses chrome.storage.local (data stays on your device)
• No Network Access: Extension operates completely offline - no data is sent to external servers

Troubleshooting

Lock screen doesn't appear?

• Refresh the page or restart Chrome
• Check if extension is enabled at chrome://extensions/

Forgot password?

• Remove and reinstall the extension
• Or delete extension data via chrome://extensions/ → Details → Clear data

Extension not working on some pages?

• Chrome internal pages (chrome://) don't allow content scripts
• Some sites with strict CSP may block the overlay

📁 Project Structure

chrome-profile-lock/
├── manifest.json              # Extension configuration (Manifest V3)
├── background.js              # Service worker (manages lock state & idle detection)
├── content.js                 # Content script (injects lock overlay)
├── lock-overlay.css           # Lock screen styles
├── popup.html                 # Extension popup UI
├── popup.js                   # Popup functionality
├── icons/                     # Extension icons
│   ├── lock-16.png
│   ├── lock-48.png
│   └── lock-128.png
├── README.md                  # This file
├── SECURITY_REVIEW.md         # Security analysis documentation
├── CONTENT_JS_REVIEW.md       # Content script review
└── PERFORMANCE_OPTIMIZATIONS.md # Performance analysis

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

📝 License

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

⚠️ Disclaimer

This extension provides a deterrent for casual access to your Chrome profile. It is not designed to protect against determined attackers with physical or administrative access to your computer. For maximum security, use OS-level user accounts and full-disk encryption.

🙏 Acknowledgments

• Built with Chrome Extensions Manifest V3
• Uses Chrome Storage API for local data persistence
• Icons designed for clarity and visibility

🤖 Development

This project was 100% built with Claude AI and Cursor. The entire codebase, documentation, and architecture were developed through AI-assisted pair programming, demonstrating the power of modern AI coding assistants.

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Made with ❤️ for privacy-conscious users