But as the device is in the attacker's hands, even a good power supply could be compromised by replacing or removing capacitors that are used to smooth out the power rails. You'd have to open the device up to do it, but eg to get at the keys inside the secure enclave on an iphone, a couple devices could be sacrificed for the cause.
> But as the device is in the attacker's hands, even a good power supply could be compromised by replacing or removing capacitors that are used to smooth out the power rails.
slightly improving the argument, while keeping the device non-compromised, is that whatever info is coming out of the LED is probably coming out in RF, also. so getting the LED further away from the CPU's power rail(s) probably isn't going to help. they're already emitting the data.
if you can stick a camera this close to the LED, you can probably surround the device with antennae, as well.
