Encrypted Instant Messengers for various devices . -Narayana KNR If you are currently using an Instant Messenger like WhatsApp, Viber, LINE, Telegram or Threema you should pick an alternative here. Mobile: Signal Signal is a mobile app developed by Open Whisper Systems. The app provides instant messaging, as well as voice and video calling. All communications are end-to-end encrypted. Signal is free and open source, enabling anyone to verify its security by auditing the code. The development team is supported by community donations and grants. There are no advertisements, and it doesn't cost anything to use. Warning: Requires a mobile number to register but you can securely use a disposable number . Download: signal.org OS: Android, iOS, macOS, Windows, Debian-based Linu...