How does getwvkeys website thing work and what does it do? (NOT HOW TO USE)

[BlueVideo10]

getwvkeys.cc I just link that one, there's a one that doesn't require Discord.

Eitherways.

How does it work when it's NOT using the Cache?


The Build Info, is literally the part that is carrying the entire process for getting the keys.


But what happens in the backend? Because it would be good and smart to learn how the backend and the process of retrieving does keys with the dumped CDM works. (Obviously only that are interested in learning or understanding how it works)

There's that RSA KEY THING and another thing that you upload to the website. Then it gets capable of getting the keys for you, but what's the process that it goes through for that? (Incase website disappears and etc., still a good thing to know though)

For Widevine DRM btw.



And that's my question in this thread. How does it work? And I am not asking how to use it. I am asking specifically the backend. The process.

[ElCap]

https://bunny.net/academy/streaming/what-is-widevine-cdm-content-decryption-module/
https://ottverse.com/eme-cenc-cdm-aes-keys-drm-digital-rights-management/

[BlueVideo10]

https://bunny.net/academy/streaming/what-is-widevine-cdm-content-decryption-module/
https://ottverse.com/eme-cenc-cdm-aes-keys-drm-digital-rights-management/

From the first article I have seen that a "something" gets sent to the CDM, that then goes to a "Cryptographic Module" like "OEMCrypto", which maybe gets the key??

Installing that OEMCrypto though, don't find good results other than Widevine from Google.


From the second article, I read that there's a "DRM Server" that apparently sends those keys???? Or at least has something on it.

Then if I scroll down further, it doesn't say "DRM Sender" but instead it says "DRM License Server".

If I modify the PSSH on a website like getwvkeys, it still gets the key aslong the License URL is right. I can replace a character in the PSSH and it would still get the correct key, without any differences. But I also only edited the front part


Something important that I took out from this was

"without the KeyID, the license server can’t look up a movie's decryption key"

The KeyID is in the .MPD though. I am never sending the .MPD to the getwvkeys though, only a PSSH. Which looks like a Base64 type of thing. And apparently that holds all the info? (Not sure)

"Anyone with the KeyID can ask the License Server for the private key (decryption key). It is up to the DRM provider to authenticate the person asking and then supply or deny the decryption key."

If we're talking about something like getRawWidevineLicense thing, that thing doesn't send me the key in form of that hash.

Though there's stuff in that License POST response, what gets done with it? Does that hold the KeyID and the Key, or just the Key?

I haven't seen the license server provide the key in it's natural form for mp4decrypt.


The other thing I took from the article was

"A separate module (CDM or Content Decryption Module) creates the license request and decrypting & decoding the content

Along with that the key never gets leaked just like that.


Widevine's CDM is from Google.



But from all the images on that article. It keeps showing that the License Server is sending the Key, that is needed to decode the video.

But how is the key taken out from the POST response, since it all looks like NULL, and etc.

Is it visible when viewed as HEX?

And how can I download the POST Response from Google Chrome's inspect element? I don't think I can copy paste the content when I view it from Inspect Element without any issues, can I?

[Quint]

Download WKS-KEYS and look into the source.

[Obo]

To summarize simplified: a MPD usually contains (but doesn't need to) a PSSH (Protection Scheme Specific Header) string. The PSSH contains the protection scheme (eg Widevine or Playready) and id's of the keys needed to decrypt the video served by the MPD. If you alter it, it usually gets invalid.

Your local CDM (Content Decryption Module) takes this PSSH and uses it as part of a cryptographically signed license request sent to the license server. The license server then validates the license request and if considered valid returns a crypted message. This message contains the keys for decrypting the video. The message itself again can only be decrypted by your local CDM (public key cryptography).

Neither the license certificate (or: your CDM) nor the keys from the license server were ever supposed to leave the hardware.

[BlueVideo10]

Download WKS-KEYS and look into the source.

That app doesn't work or at least I didn't understand how to use it. Where do you feed it the RSA and the other default_ stuff?

[Obo]

Everyone else was able to read the stickied threads in this forum, why don't you? They contain all information you've asked for...

[Karoolus]

Download WKS-KEYS and look into the source.

That app doesn't work or at least I didn't understand how to use it. Where do you feed it the RSA and the other default_ stuff?

WKS-Keys works just fine. If you don't understand it, that means you lack basic understanding of DRM, in which case:
all the info you seek is literally in the sticky threads and in the articles ElCap posted.

If you're curious about GetWVKeys: Check their Github