Certificateless Signcryption Scheme with Proxy Unsigncryption

Abstract

Firstly,this paper gives a new signcryption model,named signcryption with proxy unsigncryption.In this model,the original unsigncrypter divides messages into several subjects and delegates his unsigncryption powers to different proxies.The authorized proxies can directly unsigncrypt ciphertexts for the original unsigncrypter.Secondly,this paper gives the security model and based on certificateless public key cryptography give a concrete scheme.At last,this paper proves its security based on Weak-BDH problem.