An Identity-based Mediated Signature Scheme from Bilinear Pairing

It has always been a critical issue to find efficient methods for fast revocation of a user’s identity in identity (ID)based cryptosystems. Unfortunately, none of the previous ID-based cryptography can find a practical way. Libert et al. and Baek et al. respectively propose an ID-based mediated encryption scheme based on the practical ID-based encryption scheme from bilinear pairing due to Boneh and Franklin. Both schemes provide an efficient method for immediate revocation of a user’s identity. However, no ID-based mediated signature scheme from bilinear pairing has been found so far. The essential reason is that most of the previous ID-based signatures from bilinear pairing are no “good” enough to generate their mediated versions. In this paper, we first presents an ID-based signature scheme from bilinear pairing. It is secure against existential forgery under adaptively chosen message and ID attack in the random oracle model. Furthermore, it has the good property of addition, thus can be used to construct an efficient ID-based mediated signature scheme. Combining this scheme with one of the above two mediated encryption schemes yields a complete solution to the fast revocation of a user’s identity in ID-based cryptosystems from bilinear pairing.