they would be able to decrypt these movies using this key. Actually, no. Movies are encrypted using AACS or BD+ on the actual blu-ray disc. The player decrypt

they would be able to decrypt these movies using this key. Actually, no. Movies are encrypted using AACS or BD+ on the actual blu-ray disc. The player decrypts the disc and re-encrypts it for HDCP, which it will only do if it establishes a valid HDCP handshake with whatever device is plugged into its HDMI/DVI/DisplayPort port. For a software Blu-Ray player, the HDCP handshake is delegated to the graphics card, and the player software will refuse to run unless the operating system guarantees that the handshake has taken place. For an open source Blu-Ray player, you need the AACS/BD+ keys (which do periodically turn up, and then get changed on the next batch of discs), not HDCP.