This document outlines the security measures implemented in the File Sharing Application to ensure that user data and files remain secure.

• JWT Authentication: The application uses JSON Web Tokens (JWT) for authentication, with tokens that expire after 24 hours.
• Enhanced JWT Claims: Each token includes a unique ID and user roles for better validation and tracking.
• Strong Password Hashing: User passwords are hashed using BCrypt with appropriate work factors.
• Role-Based Access Control: Files can only be viewed, downloaded, or modified by their owners.

• File Soft-Delete: Files are never permanently deleted immediately; they are marked as deleted and can be recovered if needed.
• Secure File Access: Files can only be accessed through authenticated API endpoints that validate the user's identity.
• Content-Type Validation: The application validates and restricts file types to prevent malicious file uploads.

• CSRF Protection: Cross-Site Request Forgery protection is enabled for all endpoints except file uploads and authentication.
• CORS Configuration: Cross-Origin Resource Sharing is configured to allow only specific trusted origins.
• Content Security Policy: Strict CSP rules are defined to prevent XSS attacks.
• Secure Headers: HTTP security headers are set including:
  • X-Content-Type-Options: nosniff
  • X-XSS-Protection
  • Cache-Control: no-cache, no-store
  • Strict-Transport-Security

• HTTPS Only: In production, all communication is encrypted using HTTPS.
• Environment Variables: Sensitive configuration like JWT secrets and database credentials are stored as environment variables.
• Cookie Security: Cookies are marked as secure, HttpOnly, and SameSite=Strict.
• Production-Specific Configuration: A separate application-prod.properties file enables additional security features in production.

• Authenticated Blob URLs: For file previews, we use authenticated API calls to fetch file data and create local blob URLs rather than exposing direct file links.
• Memory Management: Blob URLs are properly revoked after use to prevent memory leaks.

1. Use Environment Variables: All sensitive configuration should be set using environment variables.
2. Set Up HTTPS: Configure a valid SSL certificate for your domain.
3. Regular Updates: Keep all dependencies updated to minimize vulnerability risks.
4. Security Monitoring: Implement logging and monitoring to detect unusual access patterns.
5. Backup Strategy: Implement regular database and file backups.

• File Encryption: Currently, files are stored unencrypted. Future versions will implement at-rest encryption.
• Rate Limiting: API rate limiting should be implemented to prevent brute force attacks.
• Multi-Factor Authentication: Future versions will support MFA for additional security.
• Audit Logging: More comprehensive audit logging for security events.