PasteBox
Paste created. It will be deleted the first time someone opens it, so don't open it yourself — just send the link.
Your text is encrypted in this browser (AES-256-GCM) before it is sent. The key lives only in the link, after the #, and browsers never send that part to the server — so the server stores data it can't read. Anyone with the full link can read the paste, so share it carefully. Add a password for a second lock, and use burn after reading for one-time secrets.