Glitching with external crowbar?


#1

Hello friends,

I am trying to learn side channel attacks with a two-part chipwhisperer-lite board. From reading the documentation, I understand that the chipwhisperer lite board itself has two integrated mosfet power grounding things (uh… crowbars?) which let you connect a power wire to the “glitch” port, and then activate a mosfet from software to connect this wire to ground for a short glitch duration.

Is it possible to use the chipwhisperer with an external crowbar (i.e. connect the board itself to something else, and have it activate an external mosfet / other thing for the duration of the glitch)?

Thankyou!


#2

Hi there,

Sure, you can definitely do this. You can see the crowbar circuit in the CW-Lite schematic - it’s on the top right of page 8. When you apply a logic high level to either of the MOSFET inputs, the glitch output acts as a short circuit to ground. If this isn’t enough for you - maybe you need even more power? - it’s definitely possible to connect an external crowbar circuit and control it in a similar manner.

Personally I’ve never needed more power than the MOSFETs on the board. Power dissipation isn’t a big deal here because the glitch pulses are so short (at worst, you’re looking at a ~20 us short circuit).