Cisco DNCS System Release 2.8.1 3.8.1 4.3.1 User Guide

Because each output device, or output port, on a DHCT or other audiovisual device performs a unique function
and resides on equipment manufactured by diverse vendors, the industry uses a variety of content-protection
methods to meet the specifications of a particular output port.

DHCTs, CableCARD modules, and OpenCable hosts use the CCI in the content as well as data embedded in the
vertical blanking interval (VBI) and Extended Data Services (XDS) to determine how and when to apply the
following forms of content protection:



Macrovision is used to protect content that is output on analog composite ports. Macrovision modifies

the NTSC signal that is output on analog composite ports to inhibit recording onto a VCR. DBDS
components and subsystems are capable of activating the Macrovision content-protection system on
digital sources. This capability enables cable system providers to inhibit copying of digital PPV and digital
VOD content through the analog outputs (RF, S-Video, or composite) of a DHCT. Note that this method
does not affect analog YPbPr component outputs, but only analog composite ports.



Digital Transmission Content Protection (DTCP) protects content that is output on the 1394 port

from being recorded, although its use is not restricted to 1394. Unless content is marked "Copy Freely,"
the stream is encrypted on this port and content is marked with the appropriate content-protection
setting (either "Copy One Generation" or "Copy Never.") Content can be encrypted and be set to "Copy
Freely." 



Copy Generation Management System/Analog (CGMS/A) protects analog outputs from being

recorded to devices such as DVD recorders and digital VCRs. The DHCT may receive CGMS/A in analog
content as VBI data. The DHCT may also receive CGMS/A in digital content as embedded XDS data. The
DHCT has the capability to output CGMS/A information on the composite and component analog outputs.
CGMS/A data is copied from the source content to the appropriate VBI line. When analog content is
encoded and recorded, CGMS/A settings are restored in a secure manner along with the content and
restored on playback.

In addition to the content-protection methods listed above, which protect against unauthorized copying of
content, the following methods are used to protect unauthorized devices from trying to obtain information (
snooping).



High-bandwidth Digital Content Protection (HDCP) protects content that is output on the Digital

Visual Interface/High-Definition Multimedia Interface™ (DVI/HDMI™) port. HDCP encrypts the high-value
content, which audiovisual devices output through a DVI/HDMI port.



CableCARD modules provide content protection for decrypted content. To prevent devices from

"snooping" on the CableCARD/Host interface (PCMCIA bus), the content is re-encrypted using Dynamic
Feedback Arrangement Scrambling Technique (DFAST). This technique "re-scrambles" the bits of a
program for hand-off to a host device, such as a TV. You can 

you believe the host has been compromised.

Note: The camPsm process uses Global Broadcast Authorization Messages (GBAMs) to control various types of
content protection. If the environment variable CC_DATA_FILE is not set when camPsm starts, the system
creates the file copyControlParams.inf for you with the default values. If the variable is set to point to a specific
file, the configuration values in that file will be used. For more information on the CC_DATA_FILE, see