Support from studios has been widely cited as the reason for Blu-ray's victory, but few consumers know that the studios were likely won over by the presence of a digital lock on movies called BD+, a far more sophisticated and resilient digital rights management, or DRM, system than that offered by HD DVD.

That is interesting... But we all know that first there will be blu-ray software, second there will be blu-ray burners, third there will be blu-ray decrypters.

How Crypto Won the DVD War | Threat Level from Wired.com