Evaluating the ROCKY Countermeasure for Side-Channel Leakage

ROCKY is a recently introduced countermeasure against fault attacks for authenticated encryption algorithms. It is based on the random rotation of the internal state. In this work, we evaluate the effectiveness of ROCKY as a countermeasure against side-channel attacks. We implement four different types of FPGA-oriented architectures of Xoodoo: an unprotected version and three different versions protected with ROCKY. Xoodoo is used as round function of Xoodyak, which is a scheme in the NIST lightweight cryptography standardization competition. For the experimental setup, the SAKURA-G target board with Spartan-6 FPGA is used. The evaluation of the results is done through test vector leakage assessment (TVLA). This is the first work looking into the side-channel security of the ROCKY countermeasure.