Tutanota, the First Encrypted Email Service with an App on F-Droid (Linux Journal)
Here's aLinux Journal article from one of the creators of the Tutanotaencrypted email client. "That's why we decided to build Tutanota: a secure email service that is so easy to use, everyone can send confidential email, not only the tech-savvy. The entire encryption process runs locally on users' devices, and it's fully automated. The automatic encryption also enabled us to build fully encrypted email apps for Android and iOS.Finally, end-to-end encrypted email is starting to become the standard: 58% of all email sent from Tutanota already are end-to-end encrypted, and the percentage is constantly rising."