CPA on External Power Source


#1

Hi,
I’m new to side-channel attacks and I’m trying to develop a countermeasure based on integrated voltage regulators as shown in the following image.
image

My expected test setup consists of a hardware-based AES engine powered by an integrated voltage regulator (either switching buck converter or linear regulator), and the power trace of the voltage regulator is to be used for correlational power analysis.

My main challenge right now is to come up with the measurement setup (as the integrated voltage regulator has been fabricated on a separate PCB).

My question is, would it possible to use chipwhisperer resources to perform power analysis on an AES engine running on one of the boards from NewAE powered by an external power source (voltage regulator)?

In addition, I’d need to perform post-signal processing such as bandpass filtering and time alignment for the measured power traces. Does ChipWhisperer offer these kind of post-signal processing functions?

Thank you in advance,
Jin


#2

Hi Jin,

There are probably several ways to do that. The CW-lite powers its target with 3.3V on the 20-pin connector; you could feed your power source to the target on this line. The CW308 UFO optionally accepts an external 5V source, but it’s conditioned before reaching the target. You can look over all the schematics on github to see what works best for your case.

ChipWhisperer has some post-processing support, see here for trace alignment. The open Python environment makes it pretty easy for you to add your own processing to the traces.

Finally if you haven’t already, have a look at these notes on overcoming internal voltage regulators in side-channel attacks.

Hope this helps,
Jean-Pierre