A Standard Model Secure Verifiably Encrypted Signature Scheme Based on Dual System

In this paper, we propose a new standard-model verifiably encrypted signature scheme (VES) based on dual system. The VES scheme is provably secure under the decisional Bilinear Diffie-Hellman and decisional Linear assumptions. Our security proof is based on a newly-introduced strategy called dual system by Waters. In our proof, we divide the signature space into two types and prove that neither type of the signature could be forged or extracted by defining a game sequences in which we can change the query signatures from one type to another one by one without the notice of the adversary.