What is hdcp function

The function of hdcp: ensure that high-definition signals transmitted by HDMI or DVI will not be illegally recorded; HDCP technical specifications are completed by Intel. When users make illegal copies, this technology will interfere and reduce the quality of the copies. image quality to protect the content.

#The operating environment of this article: Windows 7 system, Dell G3 computer.

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

HDCP protects video signals from beginning to end, which means that every link in the entire playback system must support the HDCP protocol. If the monitor does not support the HDCP protocol, it will not be able to play high-definition programs normally and can only watch to a black screen or low-quality program.

Related expansion introduction:

HDCP mainly includes three basic contents: verification protocol, pixel encryption and updateability. First, the sender verifies whether the receiving device is authorized to receive encrypted data. It verifies the validity of the data information received by the receiver through a verification protocol. The sender and the receiving device exchange a 40-bit key selection vector (KSV) with each other. The sender and the receiver perform independent operations on the obtained KSV and their own private keys. The results of the operations are compared. If the two values ​​​​are equal, the transmitter This will confirm that the receiver is an HDCP suitable receiver.

If the validity check in the previous stage is passed, the sender and receiver interact and share the key in the verification protocol part to complete the data encryption and decryption process. The encryption of the transmitter is to obtain the 24-bit encrypted pixel data by performing an "XOR" operation on the 24-bit original pixel data and the 24-bit encrypted data generated by the HDCP encryptor. After the receiver receives the encrypted pixel data, it performs an "XOR" operation with the 24-bit encrypted data encrypted by the receiver's HDCP encryptor. Since the structure and initial values ​​of the receiver HDCP encryptor are exactly the same as those of the sender HDCP encryptor, the encrypted data is restored after two "XOR" operations.

When it is necessary to de-legitimize the receiver, this is done through HDCP's updateability. This part of HDCP identifies and deactivates devices that are not authorized or whose KSV has been put on the "revocation list". This avoids the illegal theft of copyrighted information due to the private device key and KVS of the legitimate HDCP receiver being leaked for some reason.

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