A logic level countermeasure against CPA side channel attacks on AES

A novel RTL countermeasure intended to protect the AddRoundKey step of the AES algorithm against DPA or CPA attacks has been proposed and tested on an AES encoding coprocessor implemented on FPGA. Experimental results based on CPA attacks confirmed the effectiveness of the proposed countermeasure, showing that with 100000 acquired power curves, the absolute value of correlation function is one order of magnitude lower than in the non-countermeasured case and the correct key is embedded in the measured noise floor.