My understanding is that the DRM enforcement mechanism in modern display formats such as HDMI, DP and DVI are based on High-bandwidth Digital Content Protection (HDCP). This is protected by law such that:
In order to make a device that plays HDCP-enabled content, the manufacturer must obtain a license for the patent from Intel subsidiary Digital Content Protection LLC, pay an annual fee, and submit to various conditions.
I cannot find what patent this is. Wikipedia links the HDCP Specification Rev1_3 which has revision dates from 1999 to 2006. Patents tend to last 20 years in the US, so it seems likely this patent may be expiring soon.
Will the HDCP patent be expiring soon? If so, will it be legal to produce devices that freely implement this algorithm and allow copy protection to be breached?
