Send it through anywhere.
It is a locked box.
Pick a file and a password and get back an encrypted copy. From then on it can travel through email, a chat, a shared drive or a USB stick without any of them being able to read it. To open one again, drop the .hushhh file back in here: the same tool works both ways.
This browser can't run the encrypter
It needs the Web Crypto API over a secure connection. Recent Firefox, Chrome, Edge and Safari all qualify.
There is no way to recover it. Nothing about this file is stored anywhere, so a forgotten password is a lost file.
A conventional online converter takes your file, puts it on someone else's disk, does the work there and lets you download the result. Two copies of your file then exist somewhere you cannot see, for as long as that company decides. Here the code that does the work is shipped to your browser instead of your file being shipped to a server: the bytes are read by this tab, transformed in memory, and written back out as a download. Our server never sees them, so there is nothing for us to keep, log or lose.
One thing is counted, and here it is: when a tool finishes, this page tells the server which tool ran and whether it worked — never the file, its name, its size or anything read out of it, none of which ever leaves this tab. It is how we know which tools are worth keeping. The record is the same kind we keep for a one-time link: a truncated IP address, a country and a region.
Once the page has loaded, these tools keep working with the network switched off. That is the simplest proof that nothing is being sent anywhere.
Frequently Asked Questions
Q: Is the file uploaded to encrypt it?
No, and that is the point: a service that encrypted your file on its server would have held your file and your password. Everything here happens in the tab, using the browser’s built-in Web Crypto engine. Nothing is sent, so there is nothing to trust us with.
Q: What exactly is done to the file?
A 16-byte random salt is drawn, your password is stretched into a 256-bit key with PBKDF2-SHA-256 over 600,000 rounds, and the file is encrypted with AES-256-GCM under a 12-byte random nonce. The output is a small header — magic bytes, version, salt, nonce, and the original filename — followed by the ciphertext and its authentication tag.
Q: What if I forget the password?
The file is gone. There is no recovery, no reset and no back door — not as a policy but as arithmetic. Nothing about the file exists anywhere except the copy you are holding.
Q: Can it only be opened here?
It can be opened by anything that implements the format above, which is deliberately plain and written down. But in practice: keep the tool that opens it in mind before you encrypt something you will need in ten years.
Q: How big a file can I encrypt?
A few hundred megabytes, depending on the device. The file is held in the tab’s memory while it is worked on, so the ceiling is your machine rather than any server limit.
Q: How should I send the password?
Not next to the file. A one-time secret link from this site is the obvious answer: it can be opened once and then deletes itself, so an email that leaks a month later leaks a link that no longer works.
The same idea, applied to sending things rather than changing them.