Whisper Decrypt by Oleksii

Whisper Decrypt is the companion browser extension for whisper.beer —
anonymous, self-destructing, end-to-end-encryptable notes and files.

Paste the link you were given and the extension fetches the note's raw
ciphertext and decrypts it locally, right here in the popup, using your
browser's built-in Web Crypto API. It never asks any server to decrypt
anything on your behalf.

Why an extension instead of just using the website: the decryption code
ships inside this signed, reviewed package instead of being downloaded
from a server at the moment you use it — there's nothing for a
compromised or malicious server to swap out from under you.

What never leaves your device: for a standard whisper note, the
decryption key and password are used only locally and are never
transmitted — only the note's ID is. The one documented exception is a
"true end-to-end" note, where the server itself verifies the password
(it holds no key to check a derived value against) — the encryption key
itself is still never sent.

Supports:
• Standard whisper notes (text and files), with or without a password
• "True end-to-end" notes (whisper.beer's stronger optional mode)
• Self-hosted whisper-backend instances — paste any compatible link

Does not support: creating notes (read/decrypt only, for now), or
decrypting a note that used some other, custom client-side encryption
scheme — there's no safe way to guess an arbitrary format, so it says so
rather than guessing.

No account, no sign-in, no tracking, no analytics, nothing collected.

Source code, build instructions, and the full crypto implementation are
public: https://github.com/incatswetrust/whisper-extension