Hybrid Signcryption Schemes with Outsider Security

摘要

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.