Efficient key updating signature schemes based on IBS

Abstract

To mitigate the damage of secret key exposure, key updating signature schemes can be used such as a key-insulated signature scheme and an intrusion-resilient signature scheme. We propose efficient key updating signature schemes based on a secure identity-based signature (IBS) scheme. KUS-SKI is a strong (N - 1, N) key-insulated signature scheme with random-access key updates, and KUS-IR is a Type (1) intrusion-resilient signature scheme. We also provide an equivalence theorem between a secure identity-based signature scheme and a strong (N - 1, N) key-insulated signature scheme with random-access key up-dates.