Downloadable Conditional Access System or DCAS was a proposal advanced by CableLabs for secure software download of a specific Conditional Access client (computer program) which controls digital rights management (DRM) into an OCAP-compliant host consumer media device. The National Cable & Telecommunications Association (NCTA) proposed that DCAS be used as a substitute for physical CableCARDs, a standard also created by CableLabs for which products began appearing in August 2004 as part of industry compliance to the FCC mandate, which in turn is pursuant to the Telecommunications Act of 1996. DCAS is growing in popularity as a less expensive alternative for CableCARD, with major North American operator deployments from Cablevision and Charter. DCAS deployments can be expected to grow in the coming years, thanks to favorable regulatory view from the STELA Reauthorization Act of 2014 and FCC appointing a Downloadable Security Technical Advisory Committee, and wider support for key ladder (K-LAD) functionality from system-on-chip (SoC) vendors and set-top box manufacturers.
DCAS in the early days, was a controversial proposal for a variety of reasons: it did not exist, had no set deadlines for support on all cable systems, no specification even in draft form was public, may not have satisfied FCC requirements that security modules be separable, and required an operating system (OCAP) that a majority of consumer electronics (CE) manufacturers did not wish to implement. The DCAS project was abandoned by CableLabs in 2009.
DCAS, as envisioned, removed the need for physical set-top boxes or CableCARDs to protect encrypted digital content. It was proposed that instead of a card with removable circuitry, a custom ASIC chip could be soldered onto the circuitboard of any digital cable-ready device. DCAS software would then run on this custom chip. Additional circuitry needed to run the OCAP operating system would be required. OCAP programs then would be used as the sole method of interacting with DCAS since it will enable cable companies to force the download of new security software. As set-top box ASICs have now advanced to SoC implementations, the minimum hardware circuitry to store key ladders (K-LAD) is embedded in the silicon, enabling much of the security functions to be implemented in software. Further, just as traditional set-top box functionality such as user-interface and middleware are moving to the cloud, DCAS enables much of the security functions also to move to the server side or the cloud. This allows thin client set-top boxes to be deployed that can be remotely managed, in lieu of the more expensive cableCARD based systems.