High-Bandwidth Digital Content Protection (HDCP) is a form of digital copy protection and rights management developed by the Intel Corporation. It was developed to prevent digital audio and video from being copied as it travels from source to display. The system is meant to prevent HDCP-encrypted content from being displayed on unauthorized devices or devices that have been modified to copy HDCP content. A transmitter "checks" that the receiver is authorized to play its content, then encrypts it to prevent it from being copied over the connection.
HDCP uses an exchange of encryption keys between the source and the display to ensure that compliant devices will only communicate with other compliant devices. Each HDCP-compatible device contains a unique set of 40 56-bit keys as well as a special public key called a Key Selection Vector, or KSV.
Before transmitting any digital content, the transmitter and receiver exchange KSVs. The receiver will only accept content if it receives the correct KSV from the transmitter. Once the connection is established, the KSVs combine with the devices’ unique keys to create an encrypted connection. This secure connection is constantly monitored to verify the transmission. For additional protection, the transmitter encrypts the digital content before sending it. The receiver decrypts it on the other end.
HDMI sources only support a limited number of keys and some sources only accept a single key, which potentially means that the signal can only be distributed to a single display at a time. Also if a non-HDCP compliant display, such as a DVI display, is switched to the source, the video will immediately be cut and all displays will go black. The solution to this is to use a switch with its own HDCP keys on each of the outputs. By doing this the switch outputs now act as video sources and authenticate each of the displays separately, and the video source only needs to authenticate with the matrix switch input. If one of the displays is not HDCP compliant, the video to this single display can be cut without affecting the rest of the system. This ensures a faster and more reliable switching applicaton, which will be compatible with all types of HDMI sources.
Early HDCP 1.x standards protected data moving across DVI, HDMI, DisplayPort, GVIF and UDI connections. However, they did not support transmission of data across networks. The 2.x standards support transmission over any IP-based interface but limit transmission to a maximum of 32 devices.
The newer HDCP 2.2 Pro standard allows commercial AV networks to connect more devices—potentially an unlimited number. For content to be protected, all devices in the chain must be HDCP compliant and must support the same standard, e.g. HDCP 2.2. Protected source devices include set-top boxes, DVD and Blu-ray players and computer graphics cards. Receiving devices include televisions, digital projectors, video walls and computer monitors. All devices in between must support the same standard as well. These include switches, extenders, converters, repeaters, splitters and distribution amplifiers.
All HDCP-compatible equipment is licensed by Digital Content Protection. This licensing ensures that manufacturers take adequate steps to protect transmitted content or risk losing their license. Only trustworthy devices are licensed. If a device breaks the terms of the license agreement, its KSV can be added to a revocation list so future transmitters will refuse to send to the revoked device.
Because HDCP technology relies on encryption keys stored within each device, no product without these keys will work as an HDCP-compliant device. In the case of incompatibility, the display may show an error message or a snowy image.
Black Box offers a range of HDCP compatible video distribution devices such as switches, extenders, converters, repeaters, HDMI splitters and distribution amplifiers, so you can extend content from a protected-content source, ensuring the secure transmission of digital content without unauthorized individuals and devices accessing your data. Contact us today to learn more about our solutions.