After DeCSS, DVD Jon Releases DeDRMS

An anonymous reader writes "Jon Lech Johansen, who reverse engineered FairPlay back in January, and wrote the decryption code that was later used by an anonymous developer to create the playfair utility, has released a similar utility: DeDRMS. It's only 230 lines. T-shirts anyone?"

Comments

Curious how he wrote it in C#.

[brunes69]

Not that I have anything against C#, I actually find it quite nice, just stuck me as odd that someone would write a cracking toolin it. These things are traditionally written in C ( for speed ).... like DeCSS was.

Re:Curious how he wrote it in C#.

[Cthefuture]

Thanks for the link. I always like to look at what other people have tried. However, I highly doubt those results. Besides, C++ still came out on top.. eh?

For one thing they don't really test anything useful as the tests are just tight loops of very basic math stuff. His C code doesn't even compile with the VC++ compiler because he's using C99 syntax (Microsoft's compiler is not C99 compliant). And even when I fixed those problems there where a lot of warnings due to questionable variable usage. The C++ version isn't even written in C++, I wonder why there are even two separate files. Not a good start and makes me seriously question this programmers abilities.

Just a quick glance at the code suggests at least the trig benchmarks are more a test of the standard math library rather than the language. C# is going to use the same version as C/C++.

His timing methods are also questionable. Using CPU time can be highly inaccurate. It's much better to use the high precision timing functions.

I will need to take a more detailed look and do some testing of my own to see if these results are valid. Off the top of my head I will say there seems to be something screwy going on because I've never seen properly written code run faster in C#. It's just not possible. C and C++ are so close to the hardware that when written properly it is near impossible to make it faster without going to assembly. The best C# can hope for is something close to C/C++, but never better.

I'll make another post if I get time to take a more detailed look but I'm not optimistic about these tests being worth anything. Try the Language Shootout (or the win32 version) benchmarks for broader benchmarks where a lot of them have actually been looked at by programmers that know what they are doing. If you know what you are doing then you might want to really try them, don't just go by the results on the pages because some of them are skewed because the run times are way too short to be meaningful.

Again, I ask you to design a vector class in C# that uses the same or less memory than C++ and performs the same or better. It's not even close to possible.

DeDRMS

[gnu-generation-one]

"In practice, the goal of maximizing publication regardless of the cost to freedom is supported by widespread rhetoric which asserts that public copying is illegitimate, unfair, and intrinsically wrong. For instance, the publishers call people who copy "pirates," a smear term designed to equate sharing information with your neighbor with attacking a ship. (This smear term was formerly used by authors to describe publishers who found lawful ways to publish unauthorized editions; its modern use by the publishers is almost the reverse.) This rhetoric directly rejects the Constitutional basis for copyright, but presents itself as representing the unquestioned tradition of the American legal system.

The "pirate" rhetoric is typically accepted because it blankets the media so that few people realize that it is radical. It is effective because if copying by the public is fundamentally illegitimate, we can never object to the publishers' demand that we surrender our freedom to do so. In other words, when the public is challenged to show why publishers should not receive some additional power, the most important reason of all -- "We want to copy" -- is disqualified in advance.

This leaves no way to argue against increasing copyright power except using side issues. Hence opposition to stronger copyright powers today almost exclusively cites side issues, and never dares cite the freedom to distribute copies as a legitimate public value."

Misinterpreting Copyright

Source code, ideas, communication

[JoshuaDFranklin]

I am sure this will trigger another round of lawsuits, hopefully with the net effect of more education of the public and legal community as to the nature of source code as speech (that is, a method of communication).

This code shows with more simplicity than ever before how the FairPlay DRM scheme works. This can be used by programmers to add support for applications (i.e., GStreamer) to play encrypted files with a key produced from an iTunes username/password. It can be used by researchers to see any weaknesses in FairPlay and develop better methods. Unfortunately it can also be used by those who want to destroy the iTunes Music Service.

Interestingly, I believe the ideas could also be used to create files encrypted with a particular iTunes login, though perhaps I'm misunderstanding the scheme.

Re:Written in C#

[mrpuffypants]

I actually like the irony of a Microsoft pushed technology being used to kill an Apple-pushed technology THEN getting GPL'd!