Comment by rippeltippel
15 days ago
It is very possible that they process messages in the client app, before sending them.
WhatsApp does the same: have you noticed how the photos you receive have a debatable quality? Presumably (and hopefully) the sender's app downscaled them before e2e encryption.
From this it seems that whatsapp interop requires you to pass a url of the media, not the actual encrypted media. Aside from TLS, I'm not sure what encryption you get for attachments
https://engineering.fb.com/2024/03/06/security/whatsapp-mess...
You just need to enable "HD videos & photos" option in the WhatsApp settings and then the pictures and movies sent via the app have a much higher quality.