Encrypt a file to a FileX ID
Send a file that only one specific person can open — no shared password, no key in the link. FileX encrypts it to the recipient's public FileX ID so only their private key decrypts it.
Open this tool in FileX →How it works
- Open the Send Sealed tool and drop in the file to send.
- Paste the recipient's FileX ID. FileX shows a 6-word fingerprint you can confirm with them out of band.
- Optionally tick "Sign with my FileX ID" so they can verify the file came from you (ML-DSA-65).
- Encrypt and share the
.filexfile over any channel. Only the recipient's private key can open it.
Truly end-to-end, and quantum-safe
The file's key is wrapped to the recipient using a hybrid of X25519 and ML-KEM-768 combined through HKDF. Only the holder of the recipient's private key can unwrap it — not us, not your email provider, not anyone who copies the file. Because it is hybrid, it stays secure even if one of the two algorithms is later broken.
No password to leak
Unlike password sharing, there is no secret to send over a second channel and no key placed in a link. The recipient just needs their FileX ID unlocked on their device. To send to more than one person at once, add several IDs (a FileX Pro feature).
Frequently asked questions
Does the recipient need a FileX ID first?
Yes — you can only encrypt to someone who already has a FileX ID, because the file is locked to their public key. If they do not have one yet, share the file with a password instead, or ask them to create a FileX ID first.
Can you or anyone with the file read it?
No. The file is ciphertext wrapped to the recipient's key, which never leaves their device. FileX runs entirely in your browser and stores nothing — there is no server that holds the file or the key.
What does signing add?
An ML-DSA-65 signature proves the file came from your FileX ID and was not altered. On decrypt, the recipient sees your key ID and a "signature verified" result; a tampered file fails closed.