Open Source and Security Model

What is open

• The Mac app, written in Swift and SwiftUI.
• VaultCore, the library that does the cryptography, the file format and the index. It has no user interface code, so it can be read on its own.
• The file format and the threat model, in plain documents.

Source code: https://github.com/sum-eet/hiddenfolder.

Licence

The planned licence is GPL-3.0. Anyone can use, study and change the code, and forks must stay open. That also stops closed-source resellers. The signed, auto-updating download is the paid convenience. The free-plan limits exist only in the official build. If you can build it yourself, enjoy.

The security model in short

• AES-256-GCM encrypts every file, thumbnail and note with a random key.
• A key derived from your pattern with PBKDF2-HMAC-SHA512 (600,000 rounds) wraps a random master key.
• No plaintext is written to disk. Names, dates and tags live in an encrypted index.
• Analytics are off by default. Crash reports are opt-in.

The full explanation, with the key hierarchy and what is not protected, is on the security architecture page.

Audit status

Open source makes review possible. It does not prove the code is correct. Until an audit exists, treat the security claims as a design you can inspect, not as a verified result.

Verify what you download

• Compare the file's SHA-256 checksum with the one published beside the download. The free SHA-256 checker does this in your browser.
• The first beta is signed ad hoc and not notarized. The launch version is planned to be signed with a Developer ID and notarized by Apple.

Build it yourself

Build instructions will be in the repository README once it is public. You will need a Mac running macOS 14 or later with the Swift toolchain.

Report a problem

A security contact will be published with the repository. Until then use the contact details on the about page.