Build a Cloud Storage Security and Privacy Protection System

Cloud storage platforms are widely used for file sharing and backup, but without proper security, user data is vulnerable to unauthorized access and breaches. A secure cloud system with encryption and access control ensures that only authorized users can access sensitive information — preserving privacy and trust.

This system allows users to upload, store, and retrieve files on the cloud with end-to-end encryption. It includes access control via authentication, encrypted metadata, and secure file sharing via encrypted links or tokens. Files are encrypted before upload and decrypted only on authorized access.

When a user uploads a file, it is encrypted locally using AES or RSA. The encrypted file is then sent to the cloud storage server. On retrieval, the user must authenticate and the system decrypts the file locally after access is granted, ensuring no plaintext data is ever exposed server-side.

• User signs in and selects a file to upload.
• The file is encrypted using the user's key before being uploaded.
• Cloud server stores only the encrypted file and metadata.
• On download, only authorized users with the correct key can decrypt and open the file.
• Admins can view logs and manage access permissions for enterprise users.

• Web Crypto API
• CryptoJS GitHub Repository
• AWS S3 Secure Upload Guide
• Firebase Authentication Docs
• OWASP Cloud Security Guide