Second-order side-channel attacks are used to break first-order masking protections. A
practical reason which often limits the efficiency of second-order attacks is the temporal
localisation of the leaking samples. Several pairs of leakage samples must be combined
which means high computational power. For second-order attacks, the computational
complexity is quadratic. At CHES'04, Waddle and Wagner introduced attacks with complexity
O (n\log _2 n) O (n log 2 n) on traces collected from a hardware cryptographic …

Second-order side-channel attacks are used to break first-order masking protections. A
practical reason which often limits the efficiency of second-order attacks is the temporal
localisation of the leaking samples. Several leakage samples must be combined which
means high computational power. For second-order attacks, the computational complexity is
quadratic. At CHES'04, Waddle and Wagner introduced attacks with complexity $\mathcal
{O}(n\log_2 n) $ on hardware traces, where $ n $ is the window size, by working on traces …