Comment by pibaker
5 hours ago
Does turning off your phone or putting it in airplane mode provide sufficient protection against whatever attacks you are worrying about?
If your answer is yes, then you don't need a faraday cage.
If your answer is no, you are facing advanced adversary. You probably don't want a phone on you at all, faraday caged or not.
I mean to be fair, there's really no guarantee that something in the phone's hardware is neither sending nor receiving (and processing) signals. I agree though that if you're worried about being tracked or attacked, in most scenarios you're better off just not having the phone on your person.
If you for some reason do need one, it's important to know when you put a modern iPhone in airplane mode it disables cellular but leaves WiFi/Bluetooth enabled. When you disable WiFi/Bluetooth it just disconnects from the devices for a day, but doesn't actually fully disable these fully. You can verify by going into the settings app and seeing that the radios are still toggled on.
And even if you do _that_, I have no idea how the software actually disables the hardware, but it may not physically power off the chip.
Any Faraday cage, bag or not, will eliminate surveillance of the phone until it comes online. Physics wins again.