Multi-receiver Signcryption Security Model And Program

In this thesis, we first propose an efficient multi-receiver signcryption scheme which can provide confidentiality and authenticity simultaneously. Compared with the trivial multi-receiver signcryption scheme, our scheme achieves much better efficiency. To address the security issue, we formulate the first security model for multi-receiver signcryption and define strong security notions. Then we prove that our scheme satisfies these security notions in the random oracle model. This work was summarized in a paper which was submitted to "Journal of Systems and Software". We then propose an efficient multi-receiver identity based signcryption scheme which only needs one pairing computation to signcrypt a message for n receivers and can provide confidentiality and authenticity simultaneously in the multi-receiver setting. We compare our scheme with several multi-receiver constructions from the security and efficiency points of view and argue that our provably secure scheme is more efficient than other known constructions. Furthermore, we formulate security models and define strong security notions for multi-receiver identity based signcryption schemes. We also prove that our scheme satisfies these strong security requirements in the random oracle model. This work was summarized in a paper which was accepted by a famous international conference ACISP'06.