I saw demos of this at either blackhat or defcon, various methods to exfiltrate data by bitbanging pins, running garbage code, or otherwise triggering hardware

I saw demos of this at either blackhat or defcon, various methods to exfiltrate data by bitbanging pins, running garbage code, or otherwise triggering hardware or peripherals to generate unintended radio signals to be picked up at a distance. I’m pretty sure I’ve heard of old games doing this for fun too.