Attribute-based signature and its applications
In an attribute-based signature (ABS), users sign messages with any predicate of their attributes issued from an at- tribute authority. Under this notion, a signature attests not to the identity of the individual who signed a message, but a claim regarding the attributes the underlying signer possesses. In ABS, users cannot forge signatures with at- tributes they do not possess even through colluding. On the other hand, a legitimate signer remains anonymous without the fear of revocation and is indistinguishable among all the users whose attributes satisfying the predicate speci¯ed in the signature. ABS is useful in many important applications such as anonymous authentication and attribute-based mes- saging systems. In this paper, we propose two e±cient ABS construc- tions supporting °exible threshold predicate by exploring a new technique for signature signing. Compared with existed schemes, the new constructions provide better e±ciency in terms of both the computational cost and signature size. The ¯rst new construction is provably secure in the random oracle model, while the second construction does not rely on the random oracle assumption. To further reduce the trust on attribute authority, we also show an ABS construc- tion with multiple attribute authorities. It is worth noting that the security of all the proposed constructions is not re- lying on generic group. As an illustrative application, we construct an e±cient non-transferable access control system from ABS.