4 ms·
You wouldn't need to turn the backlight off, but yes, you'd need to do complicated processing on the display CPU which is already at its limit doing screen ops.
by R0b0t1 5y ago
You wouldn't need to turn the backlight off, but yes, you'd need to do complicated processing on the display CPU which is already at its limit doing screen ops.
- upofadown 5y agoIn practice the backlight would be off because the input/output pin on the controller would need to be switched to the input mode from the output mode. If the backlight was driven, that drive current would swamp out the current induced by the LED(s). See Appendix E [1]. This attack only works in very specific circumstances. [1] https://intellisec.de/pubs/2021-acsac.pdf https://intellisec.de/pubs/2021-acsac.pdf
- R0b0t1 5y agoIt would be possible to measure it while on with the right hardware. It's unlikely, yes, but chips are moving to more generality and it is kind of reasonable that we would see such overdesigned chips at some point (analog + high density IO for screen in same reusable package).