Encrypt & Decrypt a File
Lock a file or a note before you send it — or open one you have been sent.
Add something to encrypt
or
Up to 100 MB · nothing is uploaded
Protect it with a password
Create the encrypted file
Recommended · smallest output · works at any supported size
Advanced
The count is written into the file, so raising it never stops an older file opening, and whoever receives this one does not have to know which you picked.
There is deliberately no choice of cipher. AES-256-GCM is the only mode here that authenticates what it encrypts — the reason a wrong password or a tampered byte fails cleanly instead of handing back plausible rubbish. The alternatives the browser offers (CBC, CTR) have no such check, so offering them would only give you a way to pick a worse one. If a better primitive lands, it becomes a new file version that this page can still open, not a dropdown.
Other formats
A self-decrypting .html is deliberately not offered. It is exactly the pattern mail filters quarantine as HTML smuggling, and designing around a security control that exists for good reason is not something we will do.
Add the encrypted file
or
A .enc file or the armored text — it works out which
Enter the password
The file is handed straight to your downloads. It is never previewed or run.
No passwords or files are stored, sent or logged. Close the tab and nothing of this remains.