Implementation and Evaluation of an SCA-Resistant Embedded Processor

Side-channel analysis (SCA) attacks are a threat for many embedded applications which have a need for security. With embedded processors being at the very heart of such applications, it is desirable to address SCA attacks with countermeasures which "naturally" fit deployment in those processors. This paper describes our work in implementing one such protection concept in an ASIC prototype and our results from a practical evaluation of its security. We are able to demonstrate that the basic principle of limiting the "leaking" portion of the processor works rather well to reduce the side-channel leakage. From this result we can draw valuable conclusions for future embedded processor design. In order to minimize the remaining leakage, the security concept calls for the application of a secure logic style. We used two concrete secure logic styles (iMDPL and DWDDL) in order to demonstrate this increase in security. Unfortunately, neither of these logic styles seems to do a particularly good job as we were still able to attribute SCA leakage to the secure-logic part of the processor. If a better suited logic style can be employed we believe that the overall leakage of the processor can be further reduced. Thus we deem the evaluated security concept as a viable method for protecting embedded processors.