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EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

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Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#31

Post by kmeisthax »

shmerl wrote: post #14
kmeisthax wrote: post #11

Earlier quoted context omitted.

The primary purpose of content encryption tools is to trigger DMCA 1201 anti-circumention provisions to prohibit people from writing decryption tools. Nothing more and nothing less. All DRM schemes are a form of obfuscation; some particularly secure ones use hardware decoding enclaves not present on desktops that are harder to crack, but that's about it. The only practically useful DRM schemes are ones where any tool…

So all this will become a pile of wasted effort once DMCA 1201 is repealed.

DMCA 1201 is a treaty implementation and thus cannot be repealed without significant international backlash.

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#32

Post by bitwize »

grishka wrote: post #10
ponderingfish wrote: post #8

Earlier quoted context omitted.

Exactly - which is why the CDM is a contentious topic because you have no way to see what's inside it. Also, technologies such as HDCP, Trusted Execution Environment prevent the decrypted and decoded frames from being leaked. At least, that's the intention. And the CDM vendors are Google, MSFT, and Apple. There's no way they are going to leak their code :) What's really strong is the rotation of decryption keys. Cont…

IMO it isn't that hard to crack a DRM system. My understanding is that most of the protections are legal, not technical, as in, if you do it, they'll sue the hell out of you and win.

"Eventually, all DRM will be cracked" LOL. Gerhard Lengeling would like a word. He spent as much time implementing the copy protection for Notator as he did writing the program itself, which copy protection involved a dongle in the Atari ST's cartridge port. And despite crackers' best efforts, it remained uncracked for at least two decades.

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#33

Post by bitwize »

shmerl wrote: post #2

That's a good breakdown of how much effort is spent on unethical application of technology. But advertising DRM on the site: "buy DRM"? That's already disgusting.

If you know anyone involved in creative work, you would bite your tongue before saying DRM is unethical.

Such people universally, to a man (or woman) believe that unauthorized distribution of their output is unethical because it makes them unable to make money for all their hard work. Inasmuch as DRM prevents this, it is a boon to these people.

DRM is a part of life now. Without it, you would not be able to enjoy the rich variety of content available on today's internet.

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#34

Post by vengefulduck »

grishka wrote: post #26
svenpeter wrote: post #23

Earlier quoted context omitted.

Yeah, there are many trivial systems out there that mostly provide legal protection. But there are also some pretty sophisticated DRM systems that are technologically quite well implemented and take a large effort to break. BD+ is one of these for example. And maybe going to platforms where the whole hardware is specialized is not what most people have in mind when they think DRM but the basic building blocks are sim…

Thanks for linking this talk, it was indeed interesting. Especially the part where he said that "if the hack costs more than 10 games, we're fine". Indeed, you probably aren't breaking this thing unless you have millions of dollars worth of equipment and the expertise to use it. But then video game consoles are special. They were always these closed, tightly-controlled ecosystems. General-purpose devices, like phones…

Intel SGX?

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#35

Post by shmerl »

kmeisthax wrote: post #31
shmerl wrote: post #14

Earlier quoted context omitted.

So all this will become a pile of wasted effort once DMCA 1201 is repealed.

DMCA 1201 is a treaty implementation and thus cannot be repealed without significant international backlash.

Treaties can't force unconstitutional garbage, especially when passed in a corrupt undemocratic fashion: https://www.eff.org/deeplinks/2013/03/ustr-secret-copyright-...

DMCA 1201 should be repealed hard and never allowed back.

Other countries will only thank US for being the first to dump it, even if it will anger DRM proponents who like to write such corrupt laws.

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#36

Post by shmerl »

bitwize wrote: post #33
shmerl wrote: post #2

That's a good breakdown of how much effort is spent on unethical application of technology. But advertising DRM on the site: "buy DRM"? That's already disgusting.

If you know anyone involved in creative work, you would bite your tongue before saying DRM is unethical. Such people universally, to a man (or woman) believe that unauthorized distribution of their output is unethical because it makes them unable to make money for all their hard work. Inasmuch as DRM prevents this, it is a boon to these people. DRM is a part of life now. Without it, you would not be able to enjoy the…

Some people in the creative field have sense and don't respect DRM. Check Lexy Alexander's posts on this topic. Check also releases by CD Projekt Red and their DRM-free games store GOG.

We need something like this to eventually succeed and disrupt current messed up DRM situation in video too:

https://www.gog.com/forum/general/introducing_gogcom_drmfree...

DRM is and will remain unethical, no matter how much its proponents will try to whitewash it with demagoguery, claiming it's "part of life now".

And for the reference, DRM doesn't do anything good for creators. It's always a crooked tool, especially when combined with policy laundering that produces stuff like DMCA 1201.

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#37

Post by Mindwipe »

grishka wrote: post #26
svenpeter wrote: post #23

Earlier quoted context omitted.

Yeah, there are many trivial systems out there that mostly provide legal protection. But there are also some pretty sophisticated DRM systems that are technologically quite well implemented and take a large effort to break. BD+ is one of these for example. And maybe going to platforms where the whole hardware is specialized is not what most people have in mind when they think DRM but the basic building blocks are sim…

Thanks for linking this talk, it was indeed interesting. Especially the part where he said that "if the hack costs more than 10 games, we're fine". Indeed, you probably aren't breaking this thing unless you have millions of dollars worth of equipment and the expertise to use it. But then video game consoles are special. They were always these closed, tightly-controlled ecosystems. General-purpose devices, like phones…

Most GPUs now have hardware backed support for DRM. That's why those GPUs get 4K Netflix.

The compromise of Apple's T2 chip was significantly overstated.

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#38

Post by Mindwipe »

grishka wrote: post #18
brigade wrote: post #13

Earlier quoted context omitted.

For HD, you'd also need a valid vendor-signed key to do the key exchange (which would get swiftly revoked once public), and/or to crack the trusted execution environment.

> which would get swiftly revoked once public And then what happens to all those devices people bought and expect to be able to watch Netflix on?

They get downgraded to SD.

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#39

Post by josephcsible »

kmeisthax wrote: post #11
young_unixer wrote: post #4

So, the only thing stopping a user from obtaining a clean copy of the content is the fact that the CDM is closed source? What if a CDM vendor leaked the source code? I guess the DRM server would block them after a while, but before they notice, the user would have free access to the content, right?

The primary purpose of content encryption tools is to trigger DMCA 1201 anti-circumention provisions to prohibit people from writing decryption tools. Nothing more and nothing less. All DRM schemes are a form of obfuscation; some particularly secure ones use hardware decoding enclaves not present on desktops that are harder to crack, but that's about it. The only practically useful DRM schemes are ones where any tool…

> the first prohibits you from circumventing ANY technological measure (yes, even something as simple as a right-click blocker, domain lock, Youtube's rolling URL cipher, or what have you)

The law does say it has to be "effective".

Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM

#40

Post by ls65536 »

bitwize wrote: post #33
shmerl wrote: post #2

That's a good breakdown of how much effort is spent on unethical application of technology. But advertising DRM on the site: "buy DRM"? That's already disgusting.

If you know anyone involved in creative work, you would bite your tongue before saying DRM is unethical. Such people universally, to a man (or woman) believe that unauthorized distribution of their output is unethical because it makes them unable to make money for all their hard work. Inasmuch as DRM prevents this, it is a boon to these people. DRM is a part of life now. Without it, you would not be able to enjoy the…

And if you know anyone who has paid for content that suddenly they had lost access to because of shut down DRM servers or intermittent internet connectivity, then you might be inclined to think a bit differently.

Ultimately I think there needs to be a balance here, and most importantly users ought to be made more aware of what they're usually getting when purchasing DRM-protected content: a limited license to consume their paid-for content for a (possibly unspecified) period of time on a specific set of devices under certain circumstances that often lie well beyond their control.

I'd like to think that some kind of free market-based approach of consumers choosing to support the content creators who take a more balanced approach to DRM (or just avoid it entirely) would "solve" these problems, but I'm not too hopeful of this ever working out given the enormous knowledge asymmetry between content creators/distributors and consumers about how stuff like this works.

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