Identity-based key-insulated signature without random oracles

Traditional identity-based signature (IBS) schemes typically rely on the assumption that secret keys are kept perfectly secure. However with more and more cryptographic primitives are deployed on insecure devices such as mobile devices, key-exposure seems inevitable. No matter how strong the IBS scheme is, once the secret key is exposed, it will be broken completely. Therefore how to deal with this problem in IBS schemes is a worthwhile challenge. In this paper we apply the key-insulation mechanism to minimize the damage of key-exposure in IBS schemes. We propose a concrete key-insulated ID-based signature scheme. What makes our scheme attractive is that it is provably secure without random oracles.