Privnote: how self-destructing notes actually work

Privnote is a free web service for sending messages that destroy themselves after being read once. You type text into a box, press a button, and receive a unique URL. Whoever opens that URL sees the note once; after that the link is dead for everybody, including you.

There is no registration, no inbox, and no message history. The service is designed for the short-lived secret: a Wi-Fi password, a recovery code, a bank detail, a private sentence you do not want sitting in a chat log forever.

The note text is encrypted in your browser and the decryption key lives in the part of the link after the # symbol, which browsers never send to the server. That means the server stores ciphertext it cannot read on its own. This is a genuinely strong design.

The weak point is never the maths — it is the link. Anyone who obtains the URL can read the note, so the transport channel matters. Sending a Privnote link over the same messenger you were trying to avoid logging gains you very little. Add a password and share it through a second channel.

Be aware of phishing clones: many look-alike domains copy the Privnote interface and quietly keep a copy of your note. Always check the address bar before pasting anything sensitive.