Leakage-Resilient Proxy Signatures

Abstract

We design a proxy signature in the setting of leakage-resilient cryptography for the first time. Our motivation is that the proxy signatures are often used in scenarios where the signing is done in an insecure environment, e.g., the proxy key is stored in a device which is not secure enough example of IC card. In such setting, an adversary who can launch side-channel attacks may detect some leakage information about the proxy key. The traditional security models of the proxy signatures cannot provide such security. Hence we extend them to the leakage-resilient setting, and also give a concrete construction which conforms to the extended security model.