And even if you _could_ trust the baseband on your device, there’s the problem that the cell tower is running software you have no visibility of. If I were the

And even if you _could_ trust the baseband on your device, there’s the problem that the cell tower is running software you have no visibility of. If I were the NSA, that’s where I’d be focussing at least some of the attention of the “exploit people’s phones” department. If you want cellular connectivity, the cellular provider needs a real time way to identify your device and it’s location (at least down to neatest few cell towers accuracy). (And once I had some capability there, the people running the “most secure basebands/devices would be the ones I kept the closest eye on. I’ve heard my local intelligence service are very interested in phone switch on/off events, because they are a signal that someone might be attempting to evade surveillance, and the rarity of “normal people” switching their phone off (or disconnecting from the cellular network) makes it worthwhile collecting all that “metadata” so they can search it for the “interesting” cases.