Fully secure wicked identity-based encryption resilient to continual auxiliary- inputs leakage

Abstract

To allow more general key derivation patterns, the concept of wicked identity-based encryption (wicked IBE) was introduced. It is an extension of hierarchical identity based encryption (HIBE). Recently, research on leakage-resilient wicked IBE has attracted much attention for its consideration on the problem of key leakage in system. However, the existing works implement leakage resistance under the bounded leakage model and fail to capture general form of leakage attacks. Through designing the generation of the master secret key and the user secret key reasonably, a wicked IBE scheme resilient to continual auxiliary-inputs leakage is proposed in this paper. The leakage of our scheme is not only from the user secret key, but also from the master secret key. We show the scheme is proven fully secure in the standard model based on the subgroup decision assumption in composite-order bilinear groups and the Goldreich-Levin theorem in Galois field. To achieve this goal, the dual system encryption technology is exploited in the security proof. Compared with existing leakage-resilient wicked IBE, our scheme has a better performance in leakage resilience and security.