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
#2That'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.
Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM
#3Very informative article. Never knew different aspects of the DRM. However i chuckled when I saw the names Ram, Shyam and Hari. Not too often do you see any names besides Alice and Bob.
Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM
#4So, 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?
Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM
#5So, 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?
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Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM
#6So, 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?
You're completely right but the source code doesn't even need to be leaked. Just reverse engineered. How else would we pirate movies from Netflix/Amazon/etc :)
Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM
#7So, 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?
DRM is the epitome of security through obscurity.
Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM
#8So, 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?
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. Content providers rotate the keys often (at times, in the middle of a movie, and very often during a live stream) to deter people from cracking the key.
Cracking DRM can be done and the goal from the other side is to make it hard and expensive. Nothing is impossible :)
Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM
#9So, 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?
It's security through obscurity. For pure software stuff, like Widevine L3, you can just patch the browser or insert a shim to spit out the decrypted video somewhere.
Re: EME, CDM, AES, CENC, and Keys – Building Blocks of DRM
#10So, 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?
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.