Should I be worried about this? How easy is it for someone to put a high-resolution video camera close enough to the power LED on my computer for this to be a problem?
Resolution is not needed, even high FPS is not really needed if the camera has a rolling shutter. An iPhone might be enough. But the recording needs to be done when your machine is decoding something using your private key, and doing nothing else.
Ironically, you can always keep open a few pages infested with multiple video ads or other doodads that switch unpredictably, sap power, and thus add noise to your power consumption. Or run a CPU miner for some coin.
Unironically, you can just put a bit of adhesive tape over your power LED if you're really concerned that someone cares enough to stage an attack like that against you.
