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The GPU, not the TPM, is the root of hardware DRM

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Re: The GPU, not the TPM, is the root of hardware DRM

#291

Post by loeg »

soerxpso wrote: post #61
tasn wrote: post #20

Earlier quoted context omitted.

The end goal is DRM all the way to the screen. No capture cards will be allowed. It's a cat and mouse game, but I wouldn't discount these efforts as a mere speed bump. Screen enforced DRM will make things much harder. A motivated individual with the right tools and hardware hacking know how may be able to jailbreak a screen to record stuff, but that's going to make things out of reach for most people.

It doesn't matter at all how out of reach it is for most people. As long as one kid in Russia can do it, the torrent is available for everyone in the world just as soon. This has already been shown with videogame DRM like Denuvo. It's so hard to crack that only a handful of people know how, and yet they end up racing eachother so eagerly every time a new game comes out that it's usually done in under 24 hours. Unless…

Denuvo is winning, for better or worse. You can see some of the lead times for cracking these games[1][2]. It's, you know, often months+.

[1]: https://www.reddit.com/r/CrackWatch/comments/1hqd4p3/crack_w...

[2]: https://www.reddit.com/r/CrackWatch/comments/ieo7u4/crack_wa...

Re: The GPU, not the TPM, is the root of hardware DRM

#292

Post by badsectoracula »

aleph_minus_one wrote: post #290
urronglol wrote: post #283

Earlier quoted context omitted.

If that ever happened I would nerd up on low level architectures. Get a job in a trusted company. Leak the keys. The only worthy cause to apply my patience to.

> If that ever happened I would nerd up on low level architectures. Get a job in a trusted company. Leak the keys. > The only worthy cause to apply my patience to. This already happened for smartphones. Concerning your first claim: Did you attempt to get a job at such a company to leak the keys? Concerning your second claim: Did you already invest lots of personal ressources for this cause?

> This already happened for smartphones.

Sadly even in tech many people do not seem to see smartphones as real computers.

Re: The GPU, not the TPM, is the root of hardware DRM

#293

Post by badsectoracula »

kccqzy wrote: post #227
no_time wrote: post #143

The author is correct in that media DRM is tied to GPU vendors on the field right now. But hardware backed DRM can be so much more invasive beyond that. I have no doubts the long term goal of MS is to have a Windows version of Play Integrity.[0] So total control over everything that happens on your device. Just to give an example of what could happen if this becomes reality: https://en.m.wikipedia.org/wiki/Web_Enviro…

I have trouble understanding your use of the term DRM. Media DRM makes sense: the copyright holders want to "manage" their rights digitally. How is that relevant to Play Integrity or WEI? Whose right is being protected or managed? If I have an Android without Play Integrity there are certain apps that will not run, but I don't see any rights being managed here: an app developer has the right to refuse service just li…

> an app developer has the right to refuse service just like I have the right to refuse running an app.

In this case it feels like an app developer having the right to punch[0] you in the face just like you have the right to refuse being punched in the face :-P.

[0] (to use a family friendly verb)

Re: The GPU, not the TPM, is the root of hardware DRM

#294

Post by ls612 »

kbolino wrote: post #289
ls612 wrote: post #280

Earlier quoted context omitted.

I’m confused, you’re saying the TV can tell if someone is pointing a camera at it? That seems highly doubtful.

It doesn't detect the act of recording live, it detects that a piece of media was obtained via recording. So, you can still point a camera at the screen and obtain a video file without any disruption to the original signal. However, that file won't play properly on Cinavia-enabled devices.

Any computer or phone can play it back I’m sure. It’s just an MP4 file. And with Airplay or an HDMI cable your TV can too?

Re: The GPU, not the TPM, is the root of hardware DRM

#295

Post by bccdee »

magila wrote: post #121
jsheard wrote: post #94

Earlier quoted context omitted.

I think there's some kind of watermarking going on, so once a rip is released to the public they can trace it back to which device keys were used to decrypt it.

Watermarking was a problem when Widevine L1 was first introduced. Pirates seem to have found a way to scrub the watermark from their releases. Either that or someone is burning a _lot_ of cash on playback hardware judging from the rate of 4K WEB-DL releases.

Depending on the bit size of a watermark, device-based watermarking should be easy to defeat using a quorum of devices to agree on bit values. It should only take around log2(n) attackers to remove an n-bit watermark.

Re: The GPU, not the TPM, is the root of hardware DRM

#296

Post by loeg »

jdietrich wrote: post #98
geerlingguy wrote: post #29

Earlier quoted context omitted.

With how good modern screens are, and how good cameras are (and how easy both are to hack), you could always play back the video and capture the photons through the air. There was something called Macrovision back in the VHS/DVD days that tried to defeat digital/analog conversion, and I'm sure visual techniques could be devised... But I imagine someone with a good OLED and a good mirrorless camera (or even a cell pho…

Once upon a time, this was how all video-to-film transfers worked. https://en.m.wikipedia.org/wiki/Kinescope

Also called Telecine (or at least, a very related process), as in: https://en.wikipedia.org/wiki/Telecine_(copying)#Piracy

Re: The GPU, not the TPM, is the root of hardware DRM

#297

Post by cryptonector »

mike_hearn wrote: post #262
cryptonector wrote: post #233

Earlier quoted context omitted.

TPM is a missed opportunity. What I really want for security is a solid secure enclave scheme on the CPU itself so my SE code can blaze. The TPM is not programmable and is very limited, both in terms of its API and in terms of its capabilities (e.g., number of keys loaded, number of algorithms supported, ...) and in terms of its performance. My point in my above reply was to say that even if TPMs were used by GPUs th…

Despite the bad press it's received over the years, SGX is a very solid design and works pretty well. Some of the papers presenting breaks turned out to be quite misleading when I looked closely at them some years ago. If you want a general purpose TEE then you could do worse than play with it. Unfortunately it's not available on consumer hardware anymore, and in the cloud only Azure really supports it AFAIK. And you…

Amazon has their Nitro secure enclave system that's pretty easy to use. IIUC its based on isolating the code that runs it and in it onto one core set aside for just that, possibly just when it's needed. Having the SE be easy to use is a key thing. Not that the Nitro approach extends well to consumer hardware (it doesn't).

Re: The GPU, not the TPM, is the root of hardware DRM

#298

Post by tuetuopay »

saxonww wrote: post #87
zb3 wrote: post #19

Earlier quoted context omitted.

Integrated GPUs exist. Wouldn't it make more sense that the "high value" content should not be exposed to any external GPU? Then we can treat those integrated ones as part of the "TEE". That's my speculation, waiting for details.

This is the question I had about this. The reason this design works per the article is that the GPU memory is inaccessible to the OS, so the decrypted content cannot be stolen. With a unified memory architecture, is the shared GPU memory inaccessible to the CPU?

With the proper MMU settings, yes, the CPU can definitely be denied access to some memory area. This is why devices like the raspberry pi have that weird boot process (the GPU boots up, then brings up the CPU), it's a direct consequence from the SoC's set-top-box lineage.

Re: The GPU, not the TPM, is the root of hardware DRM

#299

Post by Semaphor »

badsectoracula wrote: post #292
aleph_minus_one wrote: post #290

Earlier quoted context omitted.

> If that ever happened I would nerd up on low level architectures. Get a job in a trusted company. Leak the keys. > The only worthy cause to apply my patience to. This already happened for smartphones. Concerning your first claim: Did you attempt to get a job at such a company to leak the keys? Concerning your second claim: Did you already invest lots of personal ressources for this cause?

> This already happened for smartphones. Sadly even in tech many people do not seem to see smartphones as real computers.

Not GP, and don’t have their patience anyway. But while I see them as real computers, they aren’t any that I enjoy using, so I care relatively little for them.

Re: The GPU, not the TPM, is the root of hardware DRM

#300

Post by kbolino »

ls612 wrote: post #294
kbolino wrote: post #289

Earlier quoted context omitted.

It doesn't detect the act of recording live, it detects that a piece of media was obtained via recording. So, you can still point a camera at the screen and obtain a video file without any disruption to the original signal. However, that file won't play properly on Cinavia-enabled devices.

Any computer or phone can play it back I’m sure. It’s just an MP4 file. And with Airplay or an HDMI cable your TV can too?

It's not clear to me how widely Cinavia is actually deployed. The Wikipedia article hasn't really been updated in over a decade, and that's where I'm getting my info from.

However, the detection and enforcement can theoretically be done by any device or software that has access to the audio signal. The monitor, the GPU, the playback software, the operating system, etc. could each individually decide not to play the file, making it not work. Some of those can be bypassed in various ways, some can't. But instead of computers, there are smartphones, commercial media players/receivers, and televisions/projectors, which seem the most likely places to target for enforcement, and those would affect most people.

Nevertheless, I do wonder how real this actually is. Again from the decade-old Wikipedia article, it seems like Cinavia was meant to target both recording devices and playback devices. However, the Aurora theater shooting happened not long before the article stopped getting meaningful updates, and I wonder if public safety concerns stalled its deployment. Also, the article mentions that people were finding ways to remove or neuter the signal. I also didn't encounter any problems with what I assume to be protected media (a 4K movie and a 1080p TV show), either recording my screen with my Android phone, nor with playing it back on that phone and with VLC on my Windows computer with an nVidia graphics card.

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