How it works : Encrypt a file
Drop a file in and give a password: you walk away with a strongbox nobody can open without it. Drop a strongbox in, give the password, and you get the original file back, with its name.
You have to send a sensitive document, and the only channel available is ordinary email or an attachment. Encryption solves exactly that problem: the file travels unreadable, and becomes readable again only with the password, at the other end. The channel no longer needs to be safe.
The browser has been able to do this on its own since 2017, with the same functions banks and messaging apps use. There is nothing to install, nothing to embed, and above all nothing to send: neither your file nor your password leaves the tab.
The other person needs nothing but this page and the password, passed along by a different route from the file. A password sent in the same message as the strongbox protects nothing at all.
How it works
- Drop your file in. The tool works out on its own whether it is an ordinary file to lock up, or a Workbench strongbox to open.
- Type the password. It stays visible on screen, and that is deliberate: one typo while encrypting makes the file unrecoverable, and nobody on earth can reset it.
- Click. The strongbox, or the recovered file, downloads. The original name is restored on decryption, even if the strongbox was renamed along the way.
Formats accepted
This tool does not look at the contents of your file: it encrypts bytes. There is therefore no list of formats. It only looks at the first six bytes, to know whether it has a strongbox to open rather than a file to lock.
Any file at all
A document, a photo, an archive, a spreadsheet, several files gathered into a zip: everything is encrypted the same way. The strongbox that comes out carries the .etabli extension, and the original file, its name included, is locked inside.
Its limits
100 MB per file
The browser's cryptography interface does NOT work as a stream: there is no function for feeding it a file piece by piece. The whole file, then the whole result, have to fit in memory at the same time. That is a limit of the interface, verified, and exceeding it kills the tab instead of producing a file.
A lost password means a lost file
There is no account, no server, no backup copy, no “forgot my password”. That is the exact price of the fact that nothing reaches us: we cannot help you, because we hold nothing. The password stays visible on screen while you type it, precisely for this reason.
The strongbox only opens here, or with the published method
This is not a standard format like a protected zip: it is a simple container, described publicly on the method page, that anyone can reimplement. The choice avoids embedding a library, but it means no off-the-shelf program will open the strongbox.
Encrypting does not clean your metadata
It locks it away, which is not the same thing. Once the file is decrypted, the photo still carries its date and its coordinates. If the file has a life to live afterwards, run it through the metadata tool first.
A page served over HTTPS is required
The browser refuses to give its cryptography functions to a page that is not served securely. This site is. A copy of the page opened from a local folder works too.
Questions about this tool
Are my file and my password sent anywhere?
No, and it takes ten seconds to check. Open your browser's inspector with F12, go to the “Network” tab, clear the list, then encrypt a file. Not one line appears. You can also cut your connection and encrypt offline: that is the most convincing test, and it works.
Why is the password shown in the clear?
Because it is the safer choice here, and it is deliberate. There is no account, no server, no backup: a mistyped password produces a strongbox that NOBODY will ever open, you included. Dots instead of letters would hide precisely the worst mistake you can make on this page. You are alone in front of your screen; the enemy here is not someone looking over your shoulder, it is the typo.
Which password should I choose?
A phrase of four or five unrelated words, separated by spaces. It is easier to remember, easier to dictate over the phone, and far harder to guess than a short word bristling with symbols. Avoid anything about you, a date, a name, a place: those are the first things tried.
Is this real encryption, or a trick?
It is AES-256 in GCM mode, the function supplied by the browser itself, the one banking sites and encrypted messengers use. The key is built from your password by a deliberately slow function, parameterised according to the recommendations published in 2026, which makes a guessing attack expensive. The whole method, with its numbers, is shown on the page while it works and detailed on the method page: nothing is hidden, and anyone can reimplement it.
Can I open the strongbox with another program?
No, and that limit is owned. This is not a protected zip or a locked PDF: it is a simple container whose structure is described publicly on the method page. The choice avoids embedding a library, which is the site's doctrine. If the person receiving it has to be able to open it with their usual software, this is not the right tool.
Why does the tool pause for a second before answering?
Because building the key from your password is DELIBERATELY slow: it repeats hundreds of thousands of rounds of calculation. That slowness costs you one second, once, but it multiplies by the same amount the cost to someone trying millions of passwords. An instant answer would be a bad sign.
Does encrypting strip the metadata from my photo?
No: it locks it away. Once the strongbox is opened, the photo still carries its date, its camera and its coordinates. These are two different jobs, and one does not replace the other: if the file has a life to live after being decrypted, run it through the metadata tool first.
What happens if the strongbox is damaged during transfer?
It will not open, and the tool tells you so. Encryption in GCM mode adds an authenticity seal: if a single byte has changed, the check fails and the contents are not even handed over. That is a protection, not a fault. The tool cannot tell a damaged file from a wrong password, though, and it does not pretend to.
Drop a file in and give a password: you walk away with a strongbox nobody can open without it. Drop a strongbox in, give the password, and you get the original file back, with its name.
VerifyThe proof, step by stepThe network inspector check, explained one gesture at a time, with screenshots.
The cornerThe security cornerEncrypt a file, build a strong passphrase, check that a download has not been tampered with, strip the trackers from a link.