Leakage-Resilient Signatures

Sebastian Faust, Eike Kiltz, Krzysztof Pietrzak, Guy N. Rothblum

Abstract: The strongest standard security notion for digital signature schemes is unforgeability under chosen message attacks. In practice, however, this notion can be insufficient due to “side-channel attacks” which exploit leakage of information about the secret internal state. In this work we put forward the notion of “leakage-resilient signatures,” which strengthens the standard security notion by giving the adversary the additional power to learn a bounded amount of arbitrary information about the secret state that was accessed during every signature generation. This notion naturally implies security against all side-channel attacks as long as the amount of information leaked on each invocation is bounded and “only computation leaks information.”