Elon promotes "X Chat" as private messaging but...
Elon Musk assures that even if someone put a gun to his head, he could not access your messages:
"Messages are fully encrypted, with no advertising hooks or strange "AWS dependencies," so I can't read your messages even if someone puts a gun to my head.
You will also be able to make file transfers and audio/video calls."
However, we can find this in the X help center:
https://help.x.com/en/using-x/encrypted-direct-messages
"Currently, we do not offer protection against man-in-the-middle attacks. As a result, if someone—a malicious employee or X itself as a result of a mandatory legal process—compromised an encrypted conversation, neither the sender nor the recipient would know. However, we are working on mechanisms for a future version that:
· will allow devices to verify the authenticity of the content and the origin of a message (through "signature checks"); and
· will allow a pair of users to verify the devices that have access to their encrypted conversations (through "security numbers").
When signature checks and security numbers are implemented, man-in-the-middle attacks should be difficult, if not impossible, and both senders and recipients should be alerted in case of an attack."