4 ms·
LEDs causing a side channel isn't on its own new. Aside from showing your activity, some old modems (think 2400 baud) flashed activity with each 1 or with each
by 0cVlTeIATBs 3y ago
LEDs causing a side channel isn't on its own new. Aside from showing your activity, some old modems (think 2400 baud) flashed activity with each 1 or with each 0, so that an attacker only needed to see its light reflected off a wall when the room is dark, through a window, to sniff traffic.
- hinkley 3y agoEthernet cards also used to run the LED off a transistor that keyed off of the data on the TX and RX lines which would reveal some of the bits as well. I don’t recall how they fixed that, but it was a big deal at the time. Capacitor? Optical diode? I believe I recall people using white-out or paint on the LEDs they couldn’t afford to replace. Edit: if you think about it, wire protocols have error correction built in. Most of them don’t negotiate the amount to use, it’s baked into the spec. When you’re eavesdropping you lose signal to noise ratio. When the input signal is very clean, there’s plenty of SnR to spare. It’s easier to listen to a loud argument than a quiet conspiracy.