A Pairing-Based Signcryption Scheme Using Self-Certified Public Keys

In recent years, many pairing-based signcryption schemes have been proposed. There is, however, an inherent weakness in these schemes: the private key escrow problem, in which the “trusted” private key generator (PKG) can easily impersonate any user at any time without being detected. In this paper we present a pairing-based signcryption scheme using self-certified public keys. In our scheme, users can choose their private keys independently. The public keys of users can be implicitly verified with the subsequent signature verification in a logically single step. A trusted PKG is no longer required. If the dishonest PKG impersonates an honest user to communicate with others, the user can provide a proof of treachery of the PKG afterwards, which is similar to certificate-based systems.