FileKey is an offline web app that lets you quickly encrypt and share files using passkeys. No accounts, no tracking, no backend servers. Just local, offline security powered by passkeys.
🛡️ FileKey is open source and privacy-first.
- ✅ Free & Open Source – Licensed under GPLv3.
- ✅ Accountless by Design – No logins, no tracking.
- ✅ Passkey-Based Encryption – Integrates with your existing security key or password manager.
- ✅ End-to-End Encrypted – Only you can see your data.
- ✅ Secure Sharing – Share files securely with “Share Keys”
- ✅ Offline – Runs 100% offline in your browser. Can be installed locally as a PWA.
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Create your FileKey
Generate a secure passkey stored in your password manager or security key (like iCloud Keychain or Yubikey). -
Encrypt files
Drag and drop any file into FileKey — it's immediately encrypted with AES-256. -
Decrypt files
Drop the encrypted file back in. Your passkey unlocks it quickly, locally and securely. -
Share privately
Encrypt a file for someone else using their Share Key. Only they can open it.
In order to use FileKey, you need a compatible password manager (Apple Passwords, Google Passwords, Windows Hello, etc) or a hardware security key that supports FIDO2 and PRF (like the YubiKey 5 and Bio Series). For hardware security keys, your browser and operating system both need to support WebAuthn and the PRF extension. Below is a non-exhaustive compatiblity table:
| Platform | Supported Passkey Providers | Notes |
|---|---|---|
| macOS | Apple Passwords, Yubikey | Safari ≥ 17 or Chrome ≥ 112. Yubikeys will not work in Safari. |
| Windows | Windows Hello, YubiKey | Edge ≥ 112 or Chrome ≥ 112. Requires Windows 11. |
| Linux | YubiKey (via browser) | Latest version of Chrome or Chromium-based browsers. |
| iOS | Apple Passwords | Safari ≥ 17 or Chrome ≥ 112 |
| Android | Google Passwords, Yubikey | Chrome ≥ 112 |
⚠️ Notes:
- 1Password, Proton Pass, and BitWarden won't work until they properly support PRF.
- Samsung Pass has been reported to work, despite not officially supporting PRF.
- Windows 10 and below does not support PRF, and thus won't work.
- Filekey will likely work with Chromium based browsers (e.g. Brave, Vivaldi, Opera)
FileKey first requires the generation of a passkey, that will be stored on either your password manager or security key device, using the app’s domain as the relying party. Once a passkey has been created, it can then pass a static message through WebAuthn which interacts with a PRF in order to generate a deterministic random value.
Using this deterministic random value, an HKDF with 256 bits of entropy is generated. The HKDF and a random salt is then used to derive a key to be used with AES-GCM. The derived key is then used to encrypt and decrypt the file. A new derived key is used for each additional file.
All low-level cryptographic functions performed within this process are using the web’s built-in SubtleCrypto interface of the Web Crypto API. All encrypted files use a unique randomly generated salt, composed of a 16 byte hash.
🛡️ To understand more details of the encryption process, see here.
Every FileKey user has a unique Share Key — a long string that acts like a public address. You can find it in the menu under "Your Share Key."
- Click the "Share" button next to any file.
- Enter the recipient’s Share Key (they’ll need to provide this to you).
- FileKey creates a special encrypted version only that recipient can unlock. Save and send the file (ending in
.shared_filekey) via any method — email, messaging, file transfer, etc.
- Open FileKey and authenticate.
- Drag and drop the shared file into FileKey.
- FileKey detects that it’s a shared file and decrypts it using your key.
- Your private keys never leave your device.
- Shared files are locked to a specific recipient.
- All encryption and decryption happen entirely on your device — no servers involved.
- Files are secured with AES-256 encryption.
- Your Share Key does not need to be kept secret, it can be shared openly.
🛡️ Share with confidence, knowing only your intended recipient can access the file.
🔒 filekey.app
(Best in the latest versions of Chrome, Safari, or Edge)
📜 Substack
(Our official blog)
💬 Signal Group
(Chat with us directly)