How HDCP Works

Here is an example for you to have a brief understanding of how HDCP works.

If you have a HDTV and you want to watch a high definition DVD on it, then you connect the Blue-ray disc player to the TV with a HDMI cable. As a matter of fact, the moment you begin playing the HDCP-encrypted disc on your HDTV, the authentication process starts as well.

Here is the explanation of how HDCP works. Generally speaking, the transmitting device will send a ping to the receiving device, which is similar to the behavior of a submarine. If you want the signal to work all the time, then the receiving device has to return the ping the transmitting device within the limited period of time. Otherwise, the signal will stop and you have no opportunity to watch the high definition DVD any longer. Therefore, from the above-mentioned information, we can safely come to the conclusion that the key in such process lies in the return of the ping from the receiving device to the transmitting device.

In this example, the transmitting device is the Blue-ray player and the receiving device is the HDTV. As a result, things may end up in two totally different ways. If our HDTV is compatible with HDCP, then we are free to enjoy the high definition DVD as much as possible. However, if it is not HDCP-compatible, then the signal will be stopped and the movie won’t be played at all. Thus, all we are likely to get is either an error message or a blank screen.

According to the above-mentioned example, we can safely draw the conclusion that the most important factor in this process is that your device must be HDCP-compatible. Only in this way can the HDCP-encrypted content be played on the screen.

About HDCP

HDCP, short for High-bandwidth Digital Content Protection, a digital-only content protection technology associated with HDMI and DVI interfaces, is developed by Intel Corporation. It is designed for the protection of high-value digital motion pictures, television programs, and audio for it can encrypt a digital signal with a key that requires authentication from the transmitting and receiving product. Unauthorized interception and copying between a digital set top box or digital video recorder and a digital TV or PC is thus forbidden. The only thing which enables people to get access to the signal and unlock the secured content is a license key, which is set inside of the HDMI or DVI interface.

The common products which contain HDMI or DVI interface are televisions, Blu-ray disc players, cable/satellite set-top boxes, splitters, switchers, video recorders, and computer, etc. therefore, these products can be applied into use as long as they are compatible with HDCP. However, not every product is compatible with HDCP. As a result, the compatibility issue needs to be settled down. Then, how to fix HDCP compatibility problem?

Generally speaking, the feasible way to fix the compatibility issue is to discard the original device and replace them with new ones that are compatible with HDCP or to give up using the HDMI or DVI cable. In other words, there is no way and no device can change the fact that HDMI and DVI interface is not compatible with HDCP. On the other hand, non-digital cables like coaxial, RCA, component, s-video have no such issues because HDCP is digital-only.

Nonetheless, new device which can work as a HDMI/HDCP or DVI/HDCP converter is expected to be developed. In that way, the compatibility problem can be solved easily. Moreover, all HDCP-less televisions and devices can remain useful with Blu-ray and other digital media.