Vertana (1094987) writes "HDCP stands for High-bandwidth Digital Content Protection and is used by content providers to secure digital works on the connection between digital displays. It does this by encrypting the stream of data between two digital connections (ie an HDMI to HDMI connection) and having the destination (your monitor) decode it and display the data. This has caused older displays that do not come equipped with HDCP to display high definition content (such as Blu-Ray movies) even if they have the digital ports required. In order to fight this issue, someone has now leaked the alleged HDCP Master Key. This is being discussed here and here."