Provable Secure Identity-based Threshold Proxy Signcryption Scheme

The proxy signature allows a designated person,called a proxy signer,to sign on behalf of an original signer.It has the properties of authenticity and non-repudiation of message except confidentiality.Signcryption is a technique that can encrypt and sign data together in some way,while it has merits of them.This paper presented an efficient identity-based threshold signcryption scheme in the standard model and gave its security analysis in terms of bilinear pairing technique.At last,we proved its semantic security on the hardness of Decisional Bilinear Diffie-Hellman problem and its unforgeability on the hardness of Computational Diffie-Hellman problem.