Attribute-based Signcryption And Proxy-signcryption Scheme

In our lives, there is such a demand: A company has a group with specific attributes, any one of them has the right to signcrypt a document, and they want the document can only be visited by another group with specific attributes. To meet this demand, based on bilinear pairing and attribute-based cryptosystem, we build up an attribute-based signcryption scheme. In our scheme, we use the file's attribute set to identify it, and we use an access control structure to generate each group member's private key to control his signcryption and de-signcryption rights. We also analyze the correctness and security of the scheme. The scheme has the unforgeability, non-repudiation and public confirmatory.In order to let group members delegate his signcryption right to the third one, based on the above scheme, we build up a proxy-signcryption scheme, while maintaining the attribute-based signcryption advantages, it also has proxy signcryption functionality. Finally, we prove its correctness, and prove that our scheme has the strong unforgeability, strong non-repudiation, strong authentication and public confirmatory.