Threema

Threema is an iOS and Android paid open-source end-to-end encrypted instant messaging app. Because it does not require a phone number or any other personally identifying information, the program adheres to the principles of privacy by design. This helps to anonymize the users to some extent.

Threema is an extremely secure end-to-end encrypted messaging software that protects your messages with the NaCl cryptography library. When you launch the app, it produces a one-of-a-kind Threema ID key, allowing you to use it fully anonymously – no names necessary. Alternatively, you may link your account to an email address or phone number, making it simpler for other Threema users to find you. You'll also receive a scannable QR code to show to other Threema users if you meet in person but don't want to exchange names.

In addition to the standard messaging capabilities like encrypted text, phone, picture, and video chatting, the software also provides file sharing (20MB per file), emoticons, group messaging, and a polling system for gathering input from friends and contacts. While several other secure-messaging apps that haven't reached WhatsApp or Telegram adoption levels have shifted their focus to the corporate sector in order to stay viable, Threema remains firmly entrenched in the consumer market. That is made financially viable by charging a few dollars for the app.

Deatiled information:
Self-Destructing Messages: Yes
Data Stored: As Little as Possible
Website: https://threema.ch/en