Mailvelope
Type: Tool
A browser add-on for using public key encryption with your webmail. It uses the OpenPGP standard for encrypting and signing email messages. It operates as an overlay to your Gmail Yahoo or any other web accessible email client.
Website: https://www.mailvelope.com/
OS: Windows, MacOS, Linux
Requirements: Firefox, Chrome
UI language: English, Chinese
License: GNU Affero General Public License