"WhatsApp message transmission is always encrypted, meaning that only the recipient and you can decode it. This feature doesn’t allow anybody, including Facebook, to access the transmitted data. Unfortunately, this doesn't protect your chats once they are decrypted on your smartphone." So no Facebook can read all your messages directly on your phone because they write the code in WhatsApp ...
Also: With particular Google searches, anyone can discover and join hundreds of thousands of WhatsApp groups
anyone who controls WhatsApp's servers could effortlessly insert new people into an otherwise private group, even without the permission of the administrator who ostensibly controls access to that conversation.
Le réseau social de l'avenir : Pas d'annonces, pas de surveillance institutionnelle, conception éthique et décentralisation ! Possédez vos données avec Mastodon !