Log In Get Started
Free tool

Encrypt text with a password

A message in a chat stays with the messenger for ever. Encrypt it here instead: you get one line that can be pasted into any chat or email and read only with the password. Encryption and decryption happen in your browser — we see neither the text nor the password.

Pass the password to the recipient some other way — not the one the line itself travels by.

Neither the text nor the password goes anywhere: the page computes everything inside the tab and makes no network requests.

What the recipient sees

They get a line like 404T1.iVBORw0KGgo… and the password through another channel. They open this same page, switch to "Decrypt", paste the line and the password. Nothing else is needed: no sign-up, no program, no extension.

The line can be pasted anywhere — a chat, an email, a comment, a file description. It contains no spaces or line breaks, so neither messengers nor mail clients spoil it.

What is not protected here

The contents are hidden — but not the fact of the conversation. Who sent an encrypted line to whom and when is still visible, and no cipher changes that. Second: the password. If it travels by the same channel as the line, the point is lost — the whole idea rests on the fact that usually only one of the two is intercepted.

Nearby: encrypt a file, a note that burns after reading and a password generator.

The contents are closed; the road remains

Whom you write to and when is visible even without the contents. 404 VPN closes that part, and we keep no visit logs.

How it works →

FAQ

guest@404vpn:~$ cat text-crypt-faq.md
[01] $ Why one long line instead of a block with a frame? ▸
> Because a block falls apart when forwarded. Messengers wrap lines, mail clients add indents, forums collapse spaces — and the ciphertext stops decrypting while still looking intact. One line with no spaces survives all of that and pastes anywhere.
[02] $ How is this different from encrypting a file? ▸
> Only in convenience: the crypto is the same — AES-256-GCM with a key derived from the password through a million PBKDF2 rounds. A file is handy for passing a document, a line for a couple of sentences right inside a chat, without making the recipient download anything.
[03] $ What can someone who intercepts the conversation see? ▸
> That you sent an encrypted line, how long it was and roughly when. The contents, no. Encryption cannot hide the fact of the conversation: for that you need a different channel, not a different cipher.
[04] $ Can someone decrypt a line without the password? ▸
> No. Brute force is the only way, and it runs into the length of the password: key stretching makes every attempt expensive. A short dictionary password will be found; three or four unrelated words, practically not.
[05] $ Do you store the text or the password? ▸
> No. The page makes not a single network request while encrypting or decrypting — WebCrypto does it all inside the tab. You can check in the Network tab of the developer tools: pressing the button makes nothing appear there.