What is the difference between hdcp and hdmi

1. Introduction to HDCP
　　HDCP (High-bandwidth Digital Content ProtecTIon): High-bandwidth digital content protection technology. The era of HDTV (High Definition Television) is approaching. In order to adapt to the high bandwidth of HDTV, HDMI has appeared. HDMI is a high-definition digital interface standard, it can provide a high bandwidth, lossless transmission of digital video and audio signals. In order to ensure that the high-definition signal transmitted by HDMI or DVI will not be illegally recorded, a high-bandwidth digital content protection technology, namely HDCP technology, has emerged. The HDCP technical specification is led by Intel. When users make illegal copies, the technology will interfere and reduce the quality of the copied images, thereby protecting the content.

HDCP (High-bandwidth Digital Content ProtecTIon Broadband Digital Video Protection) is used to protect the transmission of HDMI-enabled transmitters and HDMI-enabled receivers. In order to protect copyrights, it is also used in the motion image industry (such as FOX, Universal, Warner Bros, etc.). It is based on HDMI, which transmits high-speed, high-bandwidth digital content protection. Other anti-copy technologies are not suitable for HDMI. For example, Macrovision is only suitable for analog signals, and DCTP only supports 100~400M bandwidth and only adapts to IEEE-1394.

　　To obtain this technology and produce HDCP-enabled products, you must obtain a license from Digital Content ProtecTIon LLC to obtain the device key required by HDCP. It is unique, one key per device.

The payment status of Licence is as follows:

　　 You must first get HDCP confirmation (AuthenTIcation) before HDMI data transmission can be carried out. The process is as follows:

　　 When the transmitter and receiver obtain a valid device key from Digital Content Protection LLC, there will be a corresponding Identifier (KSV) (Key Selection Vector).

1) Confirm the initialization. The HDCP crypto engine of the transmitting end A generates a 64-bit pseudo-random sequence An, together with its own KSV (Aksv), and transmits it to the receiving end, and the receiving end transmits its own KSV (Bksv) and REPEATER bit to the transmitting end. Respond.

2) The transmitting end uses Akey and Bksv to calculate Km, and then Km, REPEATER, An to get Ks, Mo, R0, and the receiving end uses Bkey and Aksv to calculate Km', and then Km, REPEATER, An to get Ks' , Mo', Ro'.

　　3) When R0 = R0’, the initial confirmation of HDCP is passed.

2. HDCP future outlook

Frankly speaking, although HDCP has received widespread attention in the industry and its popularization is a foregone conclusion, from the perspective of HDCP principles, the protection process is too simple, and protection is only achieved in the external transmission process. This is quite limited in the era when computers are widely used. , This not only makes people feel that the makers are suspected of defrauding high licensing fees. And once the digital signal itself is read into the computer in a binary format, the copy process can still be realized, and the RIP method similar to DVD video discs can be used for separation.