Improved Side-Channel Analysis Attacks on Xilinx Bitstream Encryption of 5, 6, and 7 Series

Since 2012, it is publicly known that the bitstream encryption feature of modern Xilinx FPGAs can be broken by side-channel analysis. Presented at CT-RSA 2012, using graphics processing units (GPUs) the authors demonstrated power analysis attacks mounted on side-channel evaluation boards optimized for power measurements. In this work, we extend such attacks by moving to the EM side channel to examine their practical relevance in real-world scenarios. Furthermore, by following a certain measurement procedure we reduce the search space of each part of the attack from 2^{32} to 2^8, which allows mounting the attacks on ordinary workstations. Several Xilinx FPGAs from different families - including the 7 series devices - are susceptible to the attacks presented here