On the security of an novel protocol for downloadable CAS

Abstract

In 2008, Jeong et al. proposed a novel protocol for a downloadable conditional access system (DCAS). They claimed that their protocol provided mutual authentication and secure downloading of conditional access (CA) software. However we show that their protocol has a fatal weakness such that it is insecure to the impersonation attack. So, we propose the improved protocol based on their protocol. Moreover, we hope that by showing this design flaw, similar mistakes can be avoided in future designs.