Multiple leakage samples based higher order optimal distinguisher

In practice, in order to recover the secret key used by a masking device, higher order side channel attacks (HOSCA) are needed. In HOSCA, physical leakages corresponding to the processing of different sensitive intermediate values can be exploited to recover the secret key used by the target device. At ASIACRYPT 2014, Bruneau et al. proposed higher order optimal distinguisher (HOOD) to recover the secret key used by the target device, and they proved that among different styles of HOSCA, HOOD shows the best efficiency in different scenarios. In HOOD, in order to recover the secret key used by the target device, physical leakages at one leakage sample corresponding to the processing of a certain sensitive intermediate value are exploited. However, there exist more than one leakage sample that correspond to the processing of a certain sensitive intermediate value, and physical leakages contained in multiple leakage samples can be exploited to recover the secret key used by the target device. In light of this, we propose multiple leakage samples based HOOD (MLS-HOOD). We note that with MLS-HOOD, physical leakages of the target device can be sufficiently exploited to efficiently recover its secret key. In fact, we will show its advantage over HOOD and another style of HOSCA in both simulated and real scenarios.