Hybrid signcryption schemes with outsider security

Abstract

This paper expands the notion of a KEM-DEM hybrid encryption scheme to the signcryption setting by introducing the notion of a signcryption KEM, a signcryption DEM and a hybrid signcryption scheme. We present the security criteria that a signcryption KEM and DEM must satisfy in order that the overall signcryption scheme is secure against outsider attacks. We also present ECISS-KEM - a simple, efficient and provably secure example of a signcryption KEM. Lastly, we briefly discuss the problems associated with using KEMs in key establishment protocols. © Springer-Verlag Berlin Heidelberg 2005.