Encrypt a File
Lock any file with a password before you send it, using AES-256 in your own browser.
Free No signup Runs in your browser — nothing uploaded
What it does
Encrypt a File reads the whole document before doing anything, so what comes back is either valid output or a specific error with the position that caused it — not a partially rewritten file.
When you need it
Usually when something has already gone wrong: a config file an application will not load, an API response that has to be read by a human, or an export that has to be checked before it goes anywhere near a database.
Limits and caveats
Key order is preserved as it appears in the input. Very large documents are limited by your device's memory rather than by an upload cap, since the parsing happens locally. Everything happens in your browser, so the file never leaves your device.
How to encrypt a file
- Drop the file.
- Choose a password — and tell the recipient some other way than the file.
- Send the .kivo file. Only that password opens it.
Frequently asked questions
- Isn't a zip password enough?
- No. The legacy ZIP cipher is broken well enough that a laptop gets through it in minutes, and most tools still use it by default. This is AES-256-GCM with a key stretched by 310,000 rounds of PBKDF2, which is the current recommendation rather than a 1990s one.
- Can you recover my file if I forget the password?
- No, and nobody can — that is what makes it worth using. There is no copy of the key, no reset, and no back door. Write the password down somewhere safe before you send anything.
- Who else can open a .kivo file?
- Only this tool, and that is the honest limitation. Standard containers like OpenPGP would open anywhere, but shipping an implementation of one is a much bigger promise to keep correctly. For sending something to somebody you can point at this page, that trade is fine; for a long-term archive, use a tool with a standard format.
- Is the filename hidden?
- No. The name is stored in the clear so the recipient knows what they received; only the contents are encrypted. Rename the file first if the name itself is sensitive.
- Do my files get uploaded?
- No. This tool runs entirely in your browser, so the file never leaves your device.