In Proceedings of PKC 2007, vol. 4450 of LNCS, pages 166–80. Springer-Verlag, Apr. 2007.
We describe the first efficient ring signature scheme secure, without random oracles, based on standard assumptions. Our ring signatures are based in bilinear groups. For l members of a ring our signatures consist of 2l+2 group elements and require 2l+3 pairings to verify. We prove our scheme secure in the strongest security model proposed by Bender, Katz, and Morselli: namely, we show our scheme to be anonymous against full key exposure and unforgeable with respect to insider corruption. A shortcoming of our approach is that all the users’ keys must be defined in the same group.