If i understand it correctly there is no open source baseband available because of various patented technologies and it is imposible to create one. But why not treat the baseband as part of insecure transit network? I'd like to see phone where voice data and text messages would be securely encrypted before sending to baseband chip and securely decrypted on the other side. I think there would be great demand for such device but i don't see any in existence. Am i missing something?
I think its because the baseband processor can access the microphone, screen and RAM semi-directly so its pointless having any encryption when you can just "key log" the screen as the user inputs the message. Please someone correct me.
(I posted a sort of question below along these lines but not yet had a response)