Generalization of the Selective-ID Security Model for HIBS Protocols

At PKC 2006, Chatterjee and Sarkar gave a generalization of the selective-ID security model for hierarchical identity-based encryption (HIBE). Corresponding to HIBE, in this paper, a generalization of the selective-ID security model for hierarchical identity-based signature (HIBS) is first proposed. They yield a complete generalization of the selective-ID security model for hierarchical identity-based cryptosystem. We introduce two security models which allow the adversary to commit to a set of identities and in the forgery phase choose any of the previously committed identities. Two constructions of HIBS are presented which can be proved to be secure in the two models. Furthermore, one of the HIBS schemes supports an unbounded number of levels