WhatsApp is an instant messaging system owned by Meta.
History
On November 18, 2014, it was announced that WhatsApp had partnered with Open Whisper Systems to provide end-to-end encryption for its messaging services.1)
External links
1)
Marlinspike, M. (2014, November 18). Open Whisper Systems partners with WhatsApp to provide end-to-end encryption. Signal Messenger. http://archive.today/2018.11.04-174737/https://signal.org/blog/whatsapp/