Used by Edward Snowden and Twitter boss Jack Dorsey, the Signal messaging application, which has made privacy a priority, is an excellent choice for anyone who wants to be able to communicate with family and friends without having to sit on their privacy.
Born in 2014, Signal is developed by the Signal Foundation, a U.S. non-profit organization created by Moxie Marlinspike, Signal's CEO, who is also a cryptographer and security researcher, and Brian Acton, one of WhatsApp's co-founders who left the ship in 2017. The application is open source and is responsible for securing your messages using an end-to-end encryption system based on Signal Protocol, an open-source cryptographic protocol.
Also open source, Telegram is an instant messaging application that was launched in 2013 by the Dourov brothers, fierce opponents of Vladimir Putin. Focusing on the security of users and their personal data, Telegram encrypts all messages and even offers a function to send self-destructive messages.
The application obviously offers the possibility of making audio and video calls, but can also serve as a platform for file exchange. Telegram imposes no size limit on the photos, videos and documents you exchange on the platform.
Although a proprietary application, the Viber application, acquired in 2014 by Rakuten, embeds all the tools you would expect from an instant messaging application. The application allows you to send text messages, make audio and video calls, launch discussions and group calls, share files or configure self-destruct messages.
All messages exchanged on Viber are encrypted from end to end using a protocol that originates from the protocol used by Signal.