I have a CWLITE with an STM32F target board. I was wondering it it is possible to trace EMsignal with my CWLITE. And if it is possible to replace the SAM cable by an “EM-probe” ?
I couldn’t find a tutorial on that.
If you’re asking if the ChipWhisperer can do power analysis via an EM probe, the answer is yes. In fact, we sell an H-field (so just a magnetic field based probe) on Mouser: https://www.mouser.com/ProductDetail/NewAE/NAE-PBSET-PSU-03?qs=r5DSvlrkXmJzuNysELhEKw%3D%3D
Of course, you’re free to use any probe you’d like. In general, we recommend some additional amplification for these probes. For example, included in that link above is a 20dB fixed LNA.
This may be obvious. But does it make sense to have two different measurements of the same victim software ; one with EM probe and the other with our original setting (with SAM cable)
What is the difference , and which one is better in terms of “(not noisy) signal” and accuracy ?
I’m not sure how much “sense” it makes in that I don’t think you can really combine your data from both measurements. Which one will be the better choice depends on your target. Generally, measuring using a shunt resistor will give you a much better SNR; however, the EM probe has advantages too in that you can avoid inserting a shunt resistor, you have more flexibility in where you measure from (you can selectively measure only parts of a chip. Decoupling capacitors are also a good choice here), and a low frequency cutoff.