Performance improvements for SHA-3 finalists by exploiting microcontroller on-chip parallelism

As ubiquitous devices, microcontrollers are deployed in a great variety of applications many of which involve communication over insecure channels that require cryptography. Here we investigate the possibility of using on-chip coprocessors from currently available microcontrollers for increasing computational power by employing parallelism. For this we focus on the analysis of SHA-3 finalists in order to identify features that can lead to an efficient parallel implementation with on-chip coprocessors. Experimental results on a Freescale S12X family microcontroller equipped with an XGATE coprocessor are presented. In this two core environment, speedups between 18 and 73 percents are obtained for the five SHA-3 finalists. In our software implementations BLAKE proves to be the best performer, especially for short messages, followed at some range by Grøstl, then by Skein, Keccak and JH.