BobRTC

vs

aTalk

Signal is a cross-platform encrypted messaging application that has a strong focus on privacy. The application is developed by Signal Messenger LLC and provides users with features like one-to-one and group messages, which can include files, voice notes, images and videos. The software is famous for being used by the whistleblower and privacy advocate Edward Snowden who once said "I use Signal every day, it is the most scalable encryption tool we have".

Skype is a telecommunications application that specialize in providing video chat and voice calls between computers, tablets, mobile devices and consoles. The software allows you to connect with friends and business colleges worldwide. Skype provides free online calls, messaging, affordable international calling to mobiles or landlines and Skype for Business for effective collaboration among teams.

With Telegram people can communicate and via instant messaging and voice over IP. Telegram is a cloud-based software and services that have a focus on privacy, speed and security. The client was initially created by the brothers Nikolai and Pavel Durov, the creators of the Russian social network VK back in 2013. Today the application is used cross-platform by over 400 million users world-wide.