FileKey – Open Source File Encryption with Passkeys (100% Local)

I just came across a cool open-source tool that works as a web app, allowing you to encrypt files using passkeys for sharing.

I mention it because file encryption is often complicated. It’s either too complex with endless PGP keys and terminal commands or too lightweight with cloud solutions that store your data on their servers, without ensuring how it’s actually ENCRYPTED.

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AH! I GOT YOU! Yes, I know we say “encrypt”! I just wanted to trigger your obsessive-compulsive disorder, you know, that annoying person who spends their life online correcting others to spark a reflection of your own life, so you can progress like a personal development addict who’s no longer afraid to face their own flaws. I know it’s painful, and you likely feel a bit of hatred towards me right now.

Anyway, FileKey has just landed on the web and offers a radical approach: AES-256 encryption using your browser’s passkeys, 100% local, no account needed, and open source. So if you’re looking to protect your data without the fuss, this solution deserves a look.

So what do you need to encrypt exactly?

Your secret account books to prevent nosy tax officials from peeking? Compromising photos of your hairy backside you want to share with colleagues without passing through Meta’s servers? Or perhaps sensitive professional documents you need to send to a client without using company solutions that give your boss access to everything?

In all these cases, FileKey might be the ideal solution.

The concept is disarmingly simple. Rather than managing complicated passwords or encryption keys that you will inevitably lose, FileKey uses passkeys. These are modern authentication systems relying on biometrics (fingerprint, facial recognition) or physical security keys like YubiKeys.

Here’s how it works:

1. Go to filekey.app in your favorite browser.
2. Generate a passkey stored in your password manager (iCloud Keychain, Google Passwords) or on your physical security key.
3. To use the app, authenticate via this passkey—based on your device, this can be a facial scan, a fingerprint, or plugging in your physical key.
4. To encrypt a file, it’s incredibly simple: drag and drop any file into the app, and boom, a new encrypted file with the “.filekey” extension is created instantly.
5. For decryption, it’s the same principle: drag and drop the encrypted file, authenticate, and voilà, your original file is restored.

The most interesting aspect is that, unlike traditional cloud solutions, no data ever leaves your computer. The encryption and decryption process is entirely local, and the app can even work offline once loaded in your browser. This way, your files remain under your control—period.

Technically, it’s serious business since FileKey uses AES-256-GCM, the same standard employed by the U.S. government for its top-secret information. The app leverages the WebAuthn API from modern browsers and the PRF (Pseudorandom Function) to generate deterministic encryption keys. For the nerds still following, this translates into military-grade security without the usual complexity.

There’s also a neat sharing feature. Each FileKey user has a unique “Share Key,” a public key that you can share safely. To send an encrypted file to someone, simply enter their Share Key, and FileKey creates a specially encrypted version that only the recipient can unlock. You can send this file via any means… email, messaging, WeTransfer, anything, and the recipient just needs to drag and drop it into FileKey to decrypt it automatically.

Behind the scenes, this sharing employs Elliptic Curve Diffie-Hellman (ECDH) key exchange on the P-521 curve. It’s complex to explain but easy to use, ensuring your private keys never leave your device.

An important point to note: FileKey is compatible with modern systems, but not all. For it to work properly, your operating system and browser must support passkeys and the PRF extension. It works well on macOS with Safari 17+ or Chrome 112+, on Windows 11 (but not Windows 10) with recent Edge or Chrome versions, on iOS with recent Safari, and on Android with Chrome. For physical keys, YubiKey series 5 and Bio are recommended.

In short, a refreshing return to the basics of encryption and privacy fundamentals. Feels good, right? The app is still young, and its team is already planning to add features like digital vaults, secure file transfer, and decentralized backup options. I’m curious to see how this project evolves.

In any case, you’ll find all the info here!

So don’t hesitate to try the app and use it daily if you like it.