Encrypt your files on your own machine.

Nowhere. Every byte stays on your machine. The page does all the locking and unlocking right here in your browser, so your files never travel to a server. Switch the wifi off and watch it carry on working. We never see your files.

Then the file is gone for good, and this is by design. The .locker opens only with the one password you set, and we hold no copy and no back door. Pick a passphrase you will remember, hit generate if you want a strong one made for you, and write it down somewhere safe. That single password is the only key.

Very. locker uses AES-256-GCM, the same cipher trusted by banks and governments to protect their most sensitive data. Your password is stretched into the key with 600,000 rounds of PBKDF2, which makes guessing slow and costly for anyone who ever got hold of your file. With a good passphrase, this is about as safe as a file gets.

Not if your password is strong. A stolen .locker is a wall of scrambled bytes, and it gives nothing away, not even the original filename or what kind of file it was, because all of that is sealed inside the encryption too. Without your password it is useless to them.

Save a copy now and it never can. The whole unlocker is this single page, so you can keep it on a USB stick or a drive and open your .locker files on any machine, offline, forever. The code is open and readable top to bottom, so what you save is what you audit.