encrypted email sender for Gmail от HackerTyper2311

Secure HTML Mail Sender for Gmail helps you send password-protected messages
from Gmail.
When composing an email in Gmail, the extension adds a toolbar lock button
that opens a secure composer. Your message is encrypted client-side (PBKDF2 +
AES-GCM) and inserted into the email as protected content.
Recipients who have the extension installed can decrypt directly inside Gmail
by entering the password. Recipients without the extension can still use the
external decrypt page through the included button.