PassLok for Email is a Chrome and Firefox extension that adds PassLok encryption to webmail apps. Currently it supports Gmail, Yahoo, and Outlook online. It is distributed as an extension for Chrome and its derivatives at https://chrome.google.com/webstore/detail/passlok-for-email/ehakihemolfjgbbfhkbjgahppbhecclh and for Firefox at https://addons.mozilla.org/en-US/firefox/addon/passlok-for-email/
PassLok for Email is also designed to be very easy to use. The sender's Lock (public key) is added to every encrypted message, and retrieved automatically on the recipient's end so he/she does not need to bother with key management chores. The only key-management action requested of the user is entering his/her secret Password, from which the private key derives when the encryption engine is initialized. The private key is retained in memory for five minutes beyond the last use of it and then deleted. It is never stored in any way.
The extensions published in the Chrome and Firefox stores are identical, except for the manifest.json file. Those files are renamed in this repo so you know which is which.
Authentication for the latest version, which is 0.4.10:
This is the SHA256 of the .crx file obtained from the Chrome store, as described in the Help document: 8965f6eea301098bde54894d09428d5bfeaf007565232328df6f497ccc9419b4
And this is the SHA256 of the .xpi file obtained from the Firefox store: f1604be1dd1045f45e42bcb1666049c24e9a97770ac97a86d391e7b4a27c2310