Built-in Self-Test — Fixture
This runs automatically when the page loads. It seals a known test note, opens it with the right passphrase, then tries the wrong passphrase and confirms it fails. That is the proof the crypto actually works in this browser.
🔒 Seal a Note
Type a message and a passphrase. You get a sealed blob you can copy or save as a file.
🔓 Open a Drop
Paste a sealed blob and enter its passphrase. The note appears only if the passphrase is exactly right.
How it works — in plain words
Your passphrase is stretched into a strong key with PBKDF2 (310,000 rounds, random salt every time). Your note is locked with AES-GCM, which adds an authentication tag — change one character of the blob or use the wrong passphrase and decryption fails outright instead of returning garbage. The blob bundles only salt + iv + ciphertext as Base64 JSON. The passphrase itself is never stored, never sent, and disappears when you close the tab.
Try it: seal a note above, copy the blob into the Open panel, try a wrong passphrase first (it must fail), then the right one (it must open).