Countermeasures for Attacks on Satellite TV Cards using Open Receivers

Digital content providers seek to restrict usage by implementing conditional access. One such scenario is the security aspects of digital video broadcast (DVB-S). There has been a history of attacks on this technology to circumvent any security measures and some techniques have been countered by the deployment of customised/provider specific receivers. However, this leads to less choice and the duplication of equipment at the customer level. Open satellite receivers have been introduced to allow a single user to access several different services from a single piece of receiver equipment. These boxes provide a highly configurable environment with software emulations of conditional access systems that is open to abuse. The internet has allowed communities with in-depth expertise to grow up around open receiver equipment; effectively communicating attack methods as they evolve. A new level of emerging attack is a card sharing by which one legitimate user colludes to provide protected content to a larger group of illegitimate users. In this paper we propose countermeasures to protect DVB-S content against this species of attack by enforcing behavioural contracts and correct usage guidelines within the smart card.