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Encryption Intel Media IT

$350 Hardware Cracks HDMI Copy Protection 161

New submitter LBeee writes "German Researchers at the Ruhr University Bochum built an FPGA board-based man-in-the-middle attack against the HDCP copy protection used in HDMI connections. After the leak of an HDCP master key in 2010, Intel proclaimed that the copy protection was still secure, as it would be too expensive to build a system that could conduct a real-time decryption of the data stream. It has now been proven that a system can be built for around $350 (€200) to do the task. However, the solution is of no great practical use for pirates. It can easily be used to burn films from Blu-ray discs, but receivers which can deliver HDTV recordings are already available — and they provide the data in compressed form. In contrast, recording directly from an HDMI port results in a large amount of data."
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$350 Hardware Cracks HDMI Copy Protection

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  • by johanwanderer ( 1078391 ) on Friday November 25, 2011 @03:33PM (#38168194)
    Since this is only a man-in-the-middle attack, it still requires an appropriate HDCP end point for each source, basically doubling the amount of gears they need to carry.
  • by Anonymous Coward on Friday November 25, 2011 @03:43PM (#38168298)

    Why would pros touch it in the first place?
    HDMI is for end-user suckers.

  • by Sycraft-fu ( 314770 ) on Friday November 25, 2011 @04:19PM (#38168588)

    Right now I have a situation where I can't watch Blu-rays on my PC. I have everything you should need, an ideal setup even. I have a high end video card that does HDCP, I have Windows 7, I have a monitor that does HDCP, and I have a receiver that does HDCP. Everything works, looks, and sounds, great. However when I play a Blu-ray, it says "Nope."

    Why?

    Well because of the way my video and audio are hooked up. My graphics card is hooked directly via DVI to my monitor. No problems there. However it then has a second HDMI output to an HDMI soundcard, which goes HDMI to my receiver. The reason is HDMI requires a video clock to send sound and the soundcard doesn't generate one. No problem, the second out is just a mirrored output, just a dummy out to get video clock.

    However Blu-ray doesn't allow for that. No splitting the signal. Even though both devices are HDCP enabled, it won't allow it.

    So hell, I might build one of these (particularly since where I work, we have Xilinx ISE). Would solve the problem and mean any future HDCP problems are easy to solve too.

  • by CyberDragon777 ( 1573387 ) <cyberdragon777@gmail. c o m> on Friday November 25, 2011 @04:37PM (#38168736)

    That's not how it works in practice. The TV doesn't have a specific chip for decoding HDCP.

    This [analog.com] $8 chip disagrees with you.
    Load it up with some keys and you get the unencrypted audio/video stream on the output pins.

  • by amorsen ( 7485 ) <benny+slashdot@amorsen.dk> on Friday November 25, 2011 @05:45PM (#38169510)

    Each lossy compression/decompression cycle loses data. For examples. see YouTube.

    If you use an algorithm similar to the original compression algorithm, you do not have to lose much (in the best case, nothing at all). E.g. a part of how JPEG works is reducing the number of colours in little squares. If you decompress/recompress with JPEG at around the same quality level, the algorithm will notice that it doesn't need to eliminate very many colours in each square, because they magically have just the right number of colours already!

    Similarly, most movie compressions try to detect if part of the next picture matches the previous, just shifted. After compression and decompression, those areas will stand out clearly to the algorithm and it is likely that similar parameters are chosen for the recompression. You can get unlucky that the second compression picks different I-frames than the first compression did, of course. If this kind of recompression becomes popular, someone will write a tool to guess which frames are I-frames.

  • by Anonymous Coward on Friday November 25, 2011 @06:28PM (#38170094)

    I have a small A/V company (10 employees) and we fairly often get clients bringing in a bluray disc that they have made themselves and expect us to show with 10 minutes notice. Even though it is all material that they have shot and edited, the hdcp issues still usually bite us. We didn't think that this would be a problem for self made discs, but experience has shown that it usually is. We now tell clients that we can only accept video files or standard def dvd's.

    While the parent poster suggests that this is only a problem when pirating material, I can tell you for a fact that it happens all the time to non copyrighted material. I don't know if clients simply don't create the discs correctly or if the bluray players just assume that hdcp should be applied and cause a fail when connected to switching gear no matter what the content. Either way, it kills us on site.

    We do everything hdsdi, but occasionally still convert our output to hdmi for some of our older projectors. This is done at each projector because of issues with long runs of hdmi cable. Blackmagic has converters that only cost 4 or 5 hundred bucks and work fine. While hdmi is nice for your tv at home it is a terrible thing in pro applications. I really wish manufacturers would get off the bandwagon and make pro gear pro and amateur gear amateur.

  • by arglebargle_xiv ( 2212710 ) on Saturday November 26, 2011 @01:20AM (#38172830)
    I have a $35 no-name chinese-made HDMI repeater that strips HDCP from anything you feed to it. Quite useful for watching BluRay output on my old non-HDCP TV. Doing it with an FPGA is a nice trick, but doing it with off-the-shelf parts selling for $35 retail is more convenient :-).

I tell them to turn to the study of mathematics, for it is only there that they might escape the lusts of the flesh. -- Thomas Mann, "The Magic Mountain"

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