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HDCP DRM "master key" found?

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  • #11
    Probably technically possible to construct a device that pretends it's a HDCP display but in fact is just re-compresses the data to be stored on a hard disk. So yeah, other than making non-HDCP-conformant displays work on Windows, I think this is only relevant for criminals.

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    • #12
      Just remember that it has to be able to compress it in realtime and is limited to a single pass... which leads to serious compromises in terms of quality... though I suppose that with the right hardware, you could figure out a way to implement a basic DRM-free DVR with this.

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      • #13
        Originally posted by kbios View Post
        Wow.. you would need a RAID0 of two hard disks at full-speed just to *read* it in realtime!
        1.5 Gb/s... not just *ANY* two disks.... you'll have to be looking at 15k SAS disks, and you would be HIGHLY dependent on having ZERO fragmentation... and it would have to be a DEDICATED array without your OS installed there.

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        • #14
          Originally posted by nanonyme View Post
          Probably technically possible to construct a device that pretends it's a HDCP display but in fact is just re-compresses the data to be stored on a hard disk. So yeah, other than making non-HDCP-conformant displays work on Windows, I think this is only relevant for criminals.
          What you describe sounds exactly like data backup, and this is not only relevant for criminals.

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          • #15
            Originally posted by pingufunkybeat View Post
            What you describe sounds exactly like data backup, and this is not only relevant for criminals.
            I think that data backup may be limited to the encrypted version. However, the newest DMCA exemptions allow a partial unencrypted copy for various purposes, such as research.

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            • #16
              The HDCP hardware is reasonably well separated from the rest of the display hardware so we have been able to publish display programming info without having to get too close to HDCP hardware. The HDCP logic is disabled when running open or binary drivers, ie the output display stream is not HDCP encrypted, and our hope is to keep it that way (ie that there won't be too many display devices which *require* HDCP on their inputs in order to operate).

              AFAIK the deal with the "master key breakthrough" is the ability to create your own dummy "display device" which looks like an HDCP-enabled display but which is actually a digital video capture card (which would not normally receive an HDCP license). It is somewhat orthogonal to GPU and display devices.
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              • #17
                Originally posted by bridgman View Post
                The HDCP hardware is reasonably well separated from the rest of the display hardware so we have been able to publish display programming info without having to get too close to HDCP hardware. The HDCP logic is disabled when running open or binary drivers, ie the output display stream is not HDCP encrypted, and our hope is to keep it that way (ie that there won't be too many display devices which *require* HDCP on their inputs in order to operate).
                You triggered an interesting thought.... the HDCP hardware must also be reasonably separated from the UVD as well, since it must be possible to apply HDCP to non-DRM display output as well in order to be able to, for example, play a DRM-infested video within a WINDOW (or is that not possible?) since you obviously can't mix HDCP and non-HDCP signals on the same cable to the same monitor... meaning that once the final output bits are all lined up, the last (optional? Or DRM-in = HDCP-out?) step would be to run it through HDCP.

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                • #18
                  Basically it is just a matter of time until an encryption system which is used in so many devices is broken. Well maybe you can say it is an useless effort, just extra companies can sell tools to break the system first before an open solution is discovered. So who is the real winner?

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                  • #19
                    Originally posted by droidhacker View Post
                    You triggered an interesting thought.... the HDCP hardware must also be reasonably separated from the UVD as well, since it must be possible to apply HDCP to non-DRM display output as well in order to be able to, for example, play a DRM-infested video within a WINDOW (or is that not possible?) since you obviously can't mix HDCP and non-HDCP signals on the same cable to the same monitor... meaning that once the final output bits are all lined up, the last (optional? Or DRM-in = HDCP-out?) step would be to run it through HDCP.
                    Droidhacker, HDCP works as a final layer. It is just like HTTPS. when you watch an HD movie which requires HDCP your whole stream from GPU output to screen input is encrypted. UVD works on unencrypted data. The data path from CPU to GPU is also encrypted in Windows if needed but on chip data is unencrypted.

                    As Bridgman said (sorry for misspelling your name before), yes a dummy device that receives HDMI signal can be constructed and, since post-processing or acceleration is done un-encrypted, it can be captured. OTOH, AACS is already broken and BD discs are rippable. This has no point.

                    As I said before and Bridgman confirmed, UVD and HDCP units are separate. UVD can work without HDCP and, this is sound and perfect. Also about the data rate of the 1080p movies: Sorry. You don't need that bandwidth. Maybe from GPU to screen, yes but, a BD-DL is 50 gigs at most. The remaining motion is extracted from the keyframe in the movie. Only keyframe is a full frame and is a picture. Remaining frames are diffs of the previous frame that contains differential color and motion information.

                    This key can be useful for ripping HDCP envelope from HDMI signal and enabling legacy compatibility. There was such a device years ago and it was certified HDCP device. I don't remember its name though.

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                    • #20
                      Originally posted by Silent Storm View Post
                      Droidhacker, HDCP works as a final layer. It is just like HTTPS. when you watch an HD movie which requires HDCP your whole stream from GPU output to screen input is encrypted. UVD works on unencrypted data. The data path from CPU to GPU is also encrypted in Windows if needed but on chip data is unencrypted.
                      That is exactly what I said...

                      As I said before and Bridgman confirmed, UVD and HDCP units are separate. UVD can work without HDCP and, this is sound and perfect. Also about the data rate of the 1080p movies:
                      He didn't actually come out and say that. He's very cagey (understandably so) about talking about UVD and DRM related topics. I.e., just because HDCP is disconnected from the things for which AMD has released public documentation (thus allowing us open drivers) does NOT necessarily mean that there aren't some crazy links between the UVD and the HDCP.

                      Also about the data rate of the 1080p movies: Sorry. You don't need that bandwidth. Maybe from GPU to screen,
                      You seem to have missed that that is precisely what we were talking about... GPU to screen. Which is where HDCP comes in to play and hence the kind of crap you'd be messing with if you were to make use of the master key.

                      In other words, that's great that the master key has been dumped, it doesn't really help us with anything.

                      yes but, a BD-DL is 50 gigs at most. The remaining motion is extracted from the keyframe in the movie. Only keyframe is a full frame and is a picture. Remaining frames are diffs of the previous frame that contains differential color and motion information.
                      I know how that works, and it isn't relevant to the topic of HDCP.

                      This key can be useful for ripping HDCP envelope from HDMI signal and enabling legacy compatibility. There was such a device years ago and it was certified HDCP device. I don't remember its name though.
                      Whatever it was, it is no doubt banned....
                      Now though, shouldn't be too much trouble to hack a TV to give you a massive amount of unencrypted video....


                      @Q: Why do you figure that you need such massively expensive equipment to do this? It shouldn't require much more than any cheap-O off the shelf HDMI capture card and some big disks. As long as you can store the 1.5 Gbps data stream to disk in real time, you are free to decrypt at your leisure.

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