HDMI uses copy protection system called HDCP. The system is meant to stop HDCP-encrypted content from being played on devices that do not support HDCP or which have been modified to copy HDCP content. Manufacturers who want to make a device that supports HDCP must obtain a license from Intel subsidiary Digital Content Protection, pay an annual fee, and submit to various conditions. HDCP is a standard feature in televisions, cable boxes, satellite receivers and Blu-ray players in much of the modern world.
The HDCP master key that has leaked to Internet last week is legit HDCP copy protection code. The “key” was posted to the Internet on Tuesday, where it was quickly picked up.The HDCP master key in question is used to generate lower-level “device keys”. With the master key code it is possible to build devices that play copyright-protected content without having to pay for licenses.
The disclosure means, in effect, that the content flowing over the encrypted HDMI connection may be recorded and authenticated using an unlicensed device. The bitstream now can be recorded and decrypted, allowing an encrypted film to be copied – a huge blow to Hollywood which is a big fan of all kinds of DRM technologies.