The Myth of Generic DPA…and the Magic of Learning

A

generic

DPA strategy is one which is able to recover secret information from physically observable device leakage without any

a priori

knowledge about the device’s leakage characteristics. Here we provide much-needed clarification on results emerging from the existing literature, demonstrating precisely that such methods (strictly defined) are

inherently

restricted to a very limited selection of target functions. Continuing to search related techniques for a ‘silver bullet’ generic attack appears a bootless errand. However, we find that a minor relaxation of the strict definition—the incorporation of some minimal non-device-specific intuition—produces scope for

generic-emulating

strategies, able to succeed against a far wider range of targets. We present stepwise regression as an example of such, and demonstrate its effectiveness in a variety of scenarios. We also give some evidence that its practical performance matches that of ‘best bit’ DoM attacks which we take as further indication for the necessity of performing profiled attacks in the context of device evaluations.