ProtonMail - Secure email with absolutely no compromises. Get your free encrypted email account today.
PhoneLeash: SMS/MMS forwarding - PhoneLeash: SMS/MMS forwarding app offers features that let you forward your desired text messages and multimedia messages to your email or your other mobile phone so that you can access them later.
Mailvelope - Mailvelope open source project. OpenPGP in your browser.
Easy Message - Easy Message app comes up with features to help users in effortlessly sending text messages to a phone number, which is not in the contact list.
APG - Android Privacy Guard (APG) is a free and open source application for ...
Cellcrypt - Cellcrypt app provides features so you can enjoy secure conference calling, messaging, and sharing of documents.