DVD-A decoding/decrypting again

[Pitou]

Hello all,

Quick question for you.

I know that the protection on DVD-A isn't crackable yet.

But how does WinDVD 6 be able to play it?

I mean it must do the decrypting/decoding to be able to play it, right?

Thanks.

Pitou!

[Doom9]

well.. like software DVD players, DVD-A software players decode the audio the way it's meant to be decoded. For a long time, only brute-forcing the CSS encryption was possible, but at least DVD Decrypter can also perform a proper key exchange. Though I have no clue how exactly that would work. Theoretically, if you can get your hands on a document describing the entire authentication and descrambling mechanisms, and get the proper player keys (or whatever else is required for decryption), DVD-A could be beaten as well... but it was the unsafe key storate in the Xing DVD player that made a breakthrough in CSS possible.. once pandora's box was open, other angles of attack were found out.

[Pitou]

great answer!

I heard that PC DVD-ROM were unable to read the key portion of the disk. Is that true?

Or another theory.

What about snatching the bits from memory while WinDVD 6 plays the DVD-A? Like grabbing the memory part (in realtime) that contains the clear Bits/bytes and saving them back to an AOB file.

Just a thought here.

Another theory, what about looking at how WinDVD 6 process it and instead of sending it to the soundcard, send it to a file?


Thanks.

Pitou!

[Doom9]

that's how dvdrip (the first dvd rip application I can recall) operated.. we're entering a new age with DVD-A, though I'm afraid it's very limited spread makes it a loss less attractive to beat. audio CDs are quite good enough for most people. The upcoming HD video formats will be more interesting.. there the quality improvement over existing formats is more apparent.