3 ms·
// TODO remove ductape; temp fix of https://ia.cr/2023/923 Edit: Joking aside, capacitors and black tape are actual countermeasures: Fig. 15. A circuit th
by rolandog 3y ago
// TODO remove ductape; temp fix of https://ia.cr/2023/923
Edit: Joking aside, capacitors and black tape are actual countermeasures:
Fig. 15. A circuit that leaks information via its power LED (a). Counter-
measures using a capacitor (b), an additional OPAMP (c), and an existing
OPAMP (d).
And:
Consumer Side Methods. The attack can also be prevented
by placing black tape over a device’s power LED.
- jacquesm 3y agoor just snipping it.
- TedDoesntTalk 3y agoOr simply manufacturers not using LEDs to indicate activity.
- sokoloff 3y agoThis is not an intentional indication of activity, but rather just of power.
- jacquesm 3y agoThey don't. The LEDs fluctuations are a by-product of power rail fluctuation and this in turn can be detected to discover some elements of the computations involved. It's pretty subtle. This isn't like a flashing harddrive LED, it is an LED that to all intents and purposes is burning steadily. Until you look at it in more detail and you realize that it isn't quite as steady as it should be.
- qingcharles 3y agoI'd at least solder another diode across the terminals if I did that. An LED is a diode at the end of the day and breaking the circuit might break the device.
- jacquesm 3y agoNot if it is just a power LED. No circuit that I'm aware of would break if the power LED wasn't drawing power. You'd have to go out of your way to make it that way.
- qingcharles 3y agoThank you for the clarification. I've not soldered anything for a couple of decades so my knowledge is poor.
- jacquesm 3y agoI did think that your approach is very thorough, 'change nothing' is a good principle.