WhatsApp introduced end-to-end encryption by default for personal chats in 2016.
WhatsApp announced that all messages, calls, photos, videos and other communications in its latest supported versions would be protected by end-to-end encryption in April 2016. Under this model, the communication is encrypted on the sender’s device and decrypted on the recipient’s device, so WhatsApp is not supposed to be able to read the message contents while they are in transit.
WhatsApp had been working with Open Whisper Systems, the organization associated with the Signal Protocol, to develop this protection. The rollout applied broadly across one-to-one chats and group chats, though encryption did not make every aspect of a user’s activity private. Metadata, backups and device security involve separate considerations.
Messenger is a common mix-up because it is also owned by Meta and later added encrypted conversations in stages. WhatsApp is the service associated with the company-wide default end-to-end encryption announcement in 2016.