Letterbox vs. Proton Mail Comparison Chart

Who reads your mails? With regular mails you, the receiver, all mail providers and maybe others can read them. With end-to-end encrypted mails only the sender and the receivers can read them. Our iOS-App Letterbox makes end-to-end encryption easy to use, is compatible with most mail providers and supports the standard encryption protocol OpenPGP. Letterbox is similar to common mail apps but indicates the security state of incoming and outgoing mails. We disinguish between a confidential and insecure mails. Letterbox is a free open-source mail client on iOS and part of an ongoing research project at the Freie Universität Berlin, Germany. Letterbox is still under development but you can soon use the app on your device with Apple's TestFlight app.