Affiliation: NTT Laboratories
Differential Fault Analysis on AES with 192 and 256-Bit Keys
This paper describes a differential fault analysis (DFA) on AES with 192 and 256-bit keys. We show a new attack in which both 192 and 256-bit keys are retrieved within a feasible computational time. In order to verify the proposed attack and estimate the calculation time, we implement the proposed attack using C code on a PC. As a result, we successfully recover the original 192-bit key using 3 pairs of correct and faulty ciphertexts within 5 minutes, and 256-bit key using 2 pairs of correct and faulty ciphertexts and 2 pairs of correct and faulty plaintexts within 10 minutes.
Efficient Differential Fault Analysis for AES
This paper proposes improved post analysis methods for Differential Fault Analysis (DFA) against AES. In detail, we propose three techniques to improve the attack efficiency as 1) combining previous DFA methods, 2) performing a divide-and-conquer attack by considering the AES key-schedule structure, and 3) taking the linearity of the MixColumns operation into account. As a result, the expectation of the analysis time in the previous work can be reduced to about one sixteenth. Notice that these improvements are based on the detailed analysis of the previous DFA methods and the calculation time and memory cost in practical implementations. Moreover, the proposed techniques can be widely applied to DFA attacks under different assumptions.