HDCP stands for High-bandwidth Digital Content Protection. It is a form of digital copy protection for audio and video content when it is traveling across Display port (interface between a computer and its monitor) and several other interfaces. The specification scrambles the video content transmission between the source of the video (the transmitter, e.g. the computer, DVD player Home theatre) and the digital display medium, such as the monitor, TV set or a projector. Note that HDCP is not meant to counter the copying of digital content, but is to protect the integrity of the content while being transmitted. This way, content can be transmitted through either a computer or a digital television or a DVD player to a Television or monitor and the original images remain clear from any snow or static. HDCP, therefore, is meant to transmit images over high bandwidths without losing the clear crisp quality of the original content. Some protection mechanisms protect the content from being adulterated by other high-bandwidth devices that are nearby. HDCP is gaining prominence as a means of protecting content as more and more people in the world now use mobile phones, wireless Internet and other modes of technology.
Whereas DVDs and satellite television players have been using HDCP technology for quite a while now, some computers don’t employ the technology, especially the older models. Many more hardware manufacturers are increasingly using HDCP as a means to ensure that protective measures are in place. The technology comes into play once the DVD media is placed in a DVD player or a computer. The video content then checks and makes sure that the machine is HDCP compatible. If it turns out that the machine does not have a proper license in place, it will not be allowed to display HDCP material. Otherwise, the machine will be allowed to display the content visually on the TV or a computer monitor. The HDCP controls also ensure that the nearby machines will not add their content or otherwise distort the images as seen by the viewer. HDCP works in the same manner across all interfaces.
HDCP implementation requires a license from Digital Content Protection which issues a set of unique secret device keys on all allowed devices. During the process of authentication, the visual unit will only display content once it satisfies itself that the secret keys are correct. To counter any attempts to steal data or permit eavesdropping, both the transmitter and the visual medium have a shared secret code that is consistently checked throughout the transmission period. If the authentication process is carried out to completion, the transmitter will send data to the receiver in a scrambled form which will then be decrypted by the receiver and displayed in a manner intelligible to the human eye.
Both Blue Ray and HD DVD discs as well as other DVD players employ HDCP to protect content written on them. The effectiveness of HDCP as a means to completely protect content is somewhat in dispute after Cryptanalysis researchers who in a paper entitled “A Cryptanalysis of the High-bandwidth Digital Content Protection System”, claimed that there are ways to go around the protection in a manner that will usurp the authority completely, including eavesdropping and avoiding any blacklisting of devices.
For more information on HDCP read What is HDCP?
