An Id-Based Server-Aided Designcryption Signcryption Scheme

In a server-aided designcryption signcryption scheme, some time-costing computation for designcryption of a signcryption is executed by a server, and the designcrypter spend less computation than the original designcryption algorithm. Thus, it fits many applications in power-constrained equipment. In this paper, we propose an id-based server-aided designcryption signcryption scheme, and show its security under the random oracle. Besides, the receiver is able to designcrypt signcryption without pairing operator in our scheme, so the proposed scheme is very efficient.