Some Blu-ray BD+ Equipped Discs Now Duplicable, But For How Long?

By Scott M. Fulton, III, BetaNews

November 8, 2007, 3:10 PM

A mere five months after the initial specification for the long-awaited BD+ copy protection system for Blu-ray Disc was formally released, the manufacturers of the media disc backup utility AnyDVD HD released a beta that has apparently been proven capable of copying BDs equipped with BD+ protection.

The beta of version 6.1.9.6 is apparently not without problems or exceptions, as indicated by a check of manufacturer SlySoft's forums today. Users reported problems copying Fantastic Four, Live Free or Die Hard, Sunshine, The Hills Have Eyes, and Spiderman 3 - which collectively constitute the bulk of all BD+ titles currently available. 20th Century-Fox was the first label to produce BD+ titles, and continues to be a principal champion of the system.

Both HD DVD and Blu-ray utilize AACS copy protection, which utilizes an encryption scheme that relies upon player hardware or software to identify itself digitally, and use that identity to build a decryption key that can unlock encrypted content as it's being read. That scheme was famously defeated last February, and for the last several months, that defeat applied to the first generation of Blu-ray Discs as well.

In the meantime, the AACS LA licensing body has invoked its revocation key system, which is a way of making updated hardware and software incapable of playing copied media. Users can try to avoid updating, although newer HD DVD discs may include revocation key code that trips an update sequence even without users' authorization. Nonetheless, even updated software can be defeated using techniques devised by homebrew hackers, with the result being a tug-of-war going on inside users' consoles and PCs between content providers and software authors.

All of this while Congress has been making legal so-called "transformative uses" of purchased or licensed content, by way of issuing exemptions to the Digital Millennium Copyright Act.

But Congress can't yet stop content providers from engineering their own means to protect their media anyway. For Blu-ray, BD+ was intended to be a second layer of protection atop AACS. It utilizes a virtual machine which constantly runs in a protected environment, unscrambling the entire software environment in which typical AACS encryption takes place. If the virtual machine cannot verify the integrity of the environment in which it's running, supposedly it shuts down.

Exactly how BD+ equipped content knows it's being decrypted by a validated BD+ VM, though, is a little mystery. Apparently copied content from a BD+ equipped disc (when SlySoft works out all the kinks) is playable on a PC with both AnyDVD HD and PowerDVD player software installed, without the BD+ VM being present. Presumably AnyDVD HD acts as though it's the VM without actually having to be the VM - a feat which, if the details are ever divulged, may be far simpler to pull off than originally purported.

One of the reasons Blu-ray exists separately from HD DVD in the first place was the desire among studios, especially 20th Century-Fox, to implement multiple layers of copy protection rather than just one. To that end, the Blu-ray Disc Association implemented its own version of the revocation system, which in June 2006 it described (albeit with very poor grammar) as sensitive to the introduction of hacked content through the deployment of countermeasures.

"When a hack is suspected, content provider can enter into a hack study," as an early BDA document on BD+ and BD-ROM Mark watermarking explained. "Once a hack is confirmed by the manufacturer of suspected Player, then Content Provider can have developed and release BD+ Content Protection code that detects and responds to the hack."

So even if SlySoft perfects its current beta - and there's no reason to presume it won't - the same tug-of-war that now afflicts HD DVD users on one level could soon afflict BD users on two.

Taking advantage of the spotlight this development would inevitably cast on the product, its authors saw fit to insert a little open letter of sorts into its change log text file: