Comment I'm not a crypto expert but... (Score 1) 75
Sounds to me that this problem is simple to solve, even with a naive solution. Take for example a simple key agreement algorithm like Diffie-Hellman which (for the unfamiliar with the subject) allows 2 parties to reach a secret key (called K) with a simple set of math and shared parameters (which the hackers can get but can't really use them for their advantage/finding K).
With a simple key agreement and some fast cryptographic algorithm (maybe AES) all conversations could be secure no matter what the network security was. It can even be implemented on top of current protocols AFAIK. And if people suggest that the CPU power might be too great then I just would like to remember that nowadays almost every phone has a browser (even if it's a WAP browser) and that HTTPS already uses key agreement and encryption.
I also view this (suggestion of) improvement as raising the bar in protecting the public's privacy because with this protocol in place it would be very difficult/expensive for authorities to break and eavesdrop on people conversations. With a warrant however, the network providers (cell carriers and other phone services) could put in place a way for authorities to get the key to decrypt the conversation taking place.
I for one can't wait to see a green lock next to my in-call HUD.