The power traces shift on Y-axis everytime I connect Chipwhisperer Nano

Embedded Security Side Channel Power Analysis
1

I am writing a simple c code to multiply two numbers and try to collect traces. When I connect the Chipwhisperer next time, the traces are shifted along the Y-axis. Moreover, connecting the chipwhisperer nano to a different port gives me different traces. I also want to know what the unit of the traces returned is.

2

That’s related to this issue: with the CW-Nano, there is no way to make the phase between the target clock and the ADC sampling clock consistent.

There are no units: What is the unit of power measured by Chipwhisperer Capture? - #2 by coflynn

3

But in my case it is not phase shifting…it is the shift in power consumption

4

Yes, that is exactly how it would appear. The phase between the two clocks can be shifted by a very small amount (<< one clock period); this makes the power samples shift up and/or down, because they are being sampled at slightly different times.

So yes, it looks like a vertical measurement shift, but in reality it is a very small temporal shift.