Or you just hard-wire it to USB killer only and charge your phone exclusively with wireless charging.
That feels really insightful.
Saw this post earlier and was cranking some brain cycles in kinda the same way you were. My brain settled on a switch for the USB since you should just need a 5 pole/2 throw switch (think I’m using those terms correctly?) to go from regular USB function to kill mode. I think for my own peace of mind, I’d want it to be 3 throw though (normal, completely unconnected, and kill). My brain then went to the battery, which I see as the real design constraint.
Then I got to thinking about building it into a phone case. The case would need to plug in to your phone’s USB port, then have an additional external connection; it would be this connection that is switched into normal/nothing/kill mode. Cases can be pretty bulky, so tucking a battery into there would be easier and still maybe evade detection.
All that said, I think I like your idea better.
Edit: spelling
Edit 2: additional thought: if you went with the case, you’d want to have it really difficult to remove. Like, requiring undoing some screws, especially if you can get some torx or other niche screw head design (bonus points for mix and matched screw heads).
My thoughts on that are that even if the case is identified as having a false port on it, it would be so difficult to remove that the “adversary” just plugs their info stealer into it anyway.
Yeah, it (in my case, ChatGPT) has been great for helping me along with functions I’m only passingly familiar with / trying to use in new ways.
One that I was really surprised with was that it gave me a surprisingly robust, sensible, and (seemingly) well tuned-to-my-case check list of things to inspect for a used car I intend to buy. I’m already mostly familiar with what I’m doing there, but it pointed to some things I might’ve overlooked / didn’t know were points of concern for the specific vehicle I’m looking at.