VCC glitch speed


#1

Hey everyone!

I was wondering if anyone here knows how “quickly” the XMEGA board can glitch the CW305. By this I mean how soon after hitting the manual fault button in the software does the hardware respond, and then how soon after that does the pulse affect the FPGA? I figure it’s nanoseconds if not smaller, but i’m trying to find a spot to glitch and glitch it in real time, so it seems like an important question.

Thanks!
Chris


#2

Hi,

I think you are better to glitch based on some trigger. e.g. when you press the “glitch” button, arm the trigger, reset the device and configure a glitch offset after the trigger happens.
There are many thing that will affect the latency (usb being one of them 1,500 ns. min).

Secondly In my experience it is not easy to perform a single glitch hence you might need to use the repeat function.


#3

Hmm, okay. I already think 1,500 ns will be too slow. I am trying to, during an AES run, figure out where mix columns is happening based on a real time averaging of the power trace , then launch a fault at the second to last mixcolumn operation. 1,500 ns to launch the attack gives me very little time to do this averaging.

Thanks,
Chris


#4

Although actually I take my last comment back, a 1500ns glitch speed is fine in this case since I am not doing calculations in the clock cycle itself but am using past clock cycles. I am not using the manual button, but will instead have it hard coded in to do it when my averaging says so.

Chris