Traditional cryptography considers the security of cryptosystems when the attackers have no access to the secret key. However, due to the imperfect implementation of cryptosystems, the attackers are able to obtain partial secret state of the systems via side-channel attacks, which are not considered in the traditional security notions of cryptographic primitives, including digital signature, and thus break their security. Leakage-resilient cryptography was then proposed to solve the problem. Recently, Wang et al. showed that any signature scheme can be transformed to a strongly unforgeable one in the leakage setting. However, their transformation requires to change the key pair of the scheme. In this paper, we present a key-modification-free solution in both the bounded leakage model and the auxiliary input model. Specifically, we propose a black-box construction of strongly unforgeable signature scheme in the leakage setting, and show that if the underlying building blocks are leakage-resilient, so is the resulting scheme.
A Survey on Leakage-Resilient KASE for Group Data Sharing with Auxiliary Input via Cloud Storage
