A new birthday-type algorithm for attacking the fresh re-keying countermeasure

The fresh re-keying scheme is a countermeasure designed to protect low-cost devices against side-channel attacks. In this paper, we present a new birthday-type attack based on a refined reduction to Ring-LPN with a reducible polynomial. Compared with the previous research, our algorithm significantly reduces the time complexity in the 128-bit leakage model—with an SNR equal to 8.21 and at most 220 traces, for instance, the key can be recovered using 241.96 bit-operations.