The United States Federal Communications
Commission (FCC) has mandated a more open cable television system that would free the consumer from having to purchase or lease a set-top box (STB) from a single manufacturer or cable system operator. One of the problems that needed to be addressed was the number of proprietary, incompatible conditional access systems that different operators had deployed.

Recently, the FCC issued new requirements to migrate to an open system that will support flexible, downloadable security services. The
industry response has been the development of a new architecture called Downloadable Conditional Access System (DCAS). This article outlines one DCAS implementation that employs ARM TrustZone technology
as its security foundation.

Reprinted in its entirety from ARM IQ Vol. 7, No. 2, 2008