International Association
for Cryptologic Research

Masking schemes are a prominent countermeasure against power analysis and work by concealing the values that are produced during the computation through randomness. The randomness is typically injected into the masked algorithm using a so-called refreshing scheme, which is placed after each masked operation, and hence is one of the main bottlenecks for designing efficient masking schemes. The main contribution of our work is to investigate the security of a very simple and efficient refreshing scheme and prove its security in the noisy leakage model (EUROCRYPT’13). Compared to earlier constructions our refreshing is significantly more efficient and uses only n random values and $${<}2n$$ operations, where n is the security parameter. In addition we show how our refreshing can be used in more complex masked computation in the presence of noisy leakage. Our results are established using a new methodology for analyzing masking schemes in the noisy leakage model, which may be of independent interest.