Efficient identity based aggregate signcryption scheme using bilinear pairings over elliptic curves

Abstract

Signcryption is a cryptographic primitive that performs signature and encryption simultaneously at a cost significantly lower than the traditional signature-then-encryption methodology. An aggregate signature scheme is a digital signature scheme that combines n signatures on n different messages from n different users to a single signature. In this paper, we propose an aggregate signcryption scheme in the identity based setting using bilinear pairings over elliptic curves by combining aggregate signatures with signcryption schemes. We prove that our scheme is secure and satisfies the unforgeability and confidentiality in the random oracle model with the assumptions that the CBDHP and BDHP are hard. Also our scheme is public verifiable and requires constant number of pairings for aggregate verification. Comparing with previous schemes of this kind, our scheme is more efficient in computation and communication.