I built Darkdrive, a small self-hosted cloud storage app.

Files and filenames are encrypted with AES-256-GCM before hitting disk, so the filesystem contains only ciphertext.

The encryption key is not stored in one place on the server at rest. It’s split between: - a session share stored server-side - an encrypted cookie stored in the browser

Both parts are required to decrypt files. A compromised cookie or session file alone yields nothing.

The core encryption layer is published for review. The full application is not open source at this time. https://core.darkdrive.de/public/a7c3222a5c6e12bef0648266/cr...

I chose server-side encryption over fully client-side systems to keep it simple to host while still allowing features like previews, thumbnails, and easy access across devices.

Darkdrive is a single PHP application that runs on shared hosting with minimal setup. It encrypts filenames and directory names alongside file contents, and uses split-key server-side crypto.

Happy to answer questions about the threat model or implementation.