Inhibiting Card Sharing Attacks

The satellite TV industry relies heavily on the use of smart card technology at the very heart of broadcasted services that are protected by legacy conditional access systems. The process of Satellite TV signal protection is distributed amongst a number of system components, e.g. smart cards, receivers, Conditional Access Modules (CAM) and the content provider. However, the introduction of “Open” Satellite Receivers, providing a highly configurable environment with software emulation of conditional access systems, enabled the implementation of whole range of new attacks. A widely deployed attack is often referred to as the “card sharing” attack, by which one legitimate user colludes to provide protected content to a larger group of unauthorised users. This paper proposes a countermeasure that increases the bandwidth requirements of this attack to the point where it is no longer practical with a standard internet connection, with a minimal impact on existing protocols and architectures.