Improved Differential Fault Analysis on CLEFIA

We propose a more efficient differential fault analysis (DFA) attack on CLEFIA, the 128-bit block cipher developed by Sony Corporation in 2007. In the previous study, the most efficient DFA attack on CLEFIA with a 128-bit key uses approximately 18 pairs of correct and faulty ciphertexts. We develop a new attack method and show that only 2 pairs of correct and faulty ciphertexts are needed to retrieve the 128-bit key. The proposed attack uses a characteristic of the CLEFIA algorithm,a four-branch generalized Feistel structure with four 32-bit data lines. The simulation results of the proposed attack show that it takes less than 1 minute for 74.1% of a total simulation times, and less than 1 hour for 98.1% when using a PC.