Questions about Widevine Response

[Rathan]

Hi, I have 2 questions...

1) What contains a widevine response and how it converts into key, that is what are the inputs that need the algorithm to obtain the key.
2) How can I extract the IV key from a widevine response?

[codehound]

Hi, I have 2 questions...


2) How can I extract the IV key from a widevine response?

You are confusing 2 different types of 'protection' here

[gnodde]

This might help you.. and if not, it is still a pretty decent read

https://ottverse.com/widevine-drm-how-does-it-work/

[Rathan]

You are confusing 2 different types of 'protection' here

From a decryption code, the IV key is used to obtain the final key:

license = License.read(licenseResponse.msg);
...
currentKey of license.key
...
keyId = currentKey.id;
keyData = currentKey.key.slice(0, 16); 
keyIv = currentKey.iv.slice(0, 16);
...

So I thought that in the Widevine Response there was the IV key.
I wanted to try to decrypt a video with DRM WIDEVINE using AES-128 with KEY and IV, always if it is possible

[Rathan]

[Attachment 64144 - Click to enlarge]

This might help you.. and if not, it is still a pretty decent read

https://ottverse.com/widevine-drm-how-does-it-work/

So even if the coded key is the same, every time you get different Widevine Response and can't be stored to view the video in later sessions?

Thanks

[codehound]

So I thought that in the Widevine Response there was the IV key.

I wanted to try to decrypt a video with DRM WIDEVINE using AES-128 with KEY and IV, always if it is possible

Widevine is one type of encryption, AES-128 is another type of encryption (but it isnt Widevine).

Like I said before you are confusing 2 differing types of encryption.

Is the video you want to download encrypted by WV or AES-128 ?

In either case, because you dont know, give us the url of the page that contains the video, so we can look. Both need a different approach.

[Rathan]

Widevine is one type of encryption, AES-128 is another type of encryption (but it isnt Widevine).

Like I said before you are confusing 2 differing types of encryption.

Is the video you want to download encrypted by WV or AES-128 ?

In either case, because you dont know, give us the url of the page that contains the video, so we can look. Both need a different approach.

I know they are different, but since the widevine algorithm speaks of key IV, I thought I could use it for a decryption in AES-128.

Thank you for the notions.

[basedcel]

So I thought that in the Widevine Response there was the IV key.

I wanted to try to decrypt a video with DRM WIDEVINE using AES-128 with KEY and IV, always if it is possible

Widevine is one type of encryption, AES-128 is another type of encryption (but it isnt Widevine).

Like I said before you are confusing 2 differing types of encryption.

Is the video you want to download encrypted by WV or AES-128 ?

In either case, because you dont know, give us the url of the page that contains the video, so we can look. Both need a different approach.

Not quite.

Widevine is just a secure mechanism for exchanging the encryption keys (AES 128) between the client and the server in a way such that the keys and content are never revealed to the end user. They are NOT separate mechanisms but one incorporates the other.

[Rathan]

Not quite.

Widevine is just a secure mechanism for exchanging the encryption keys (AES 128) between the client and the server in a way such that the keys and content are never revealed to the end user. They are NOT separate mechanisms but one incorporates the other.

Here is explained!
So it's right that there is also a key IV inside, which then turns into the KID:KEY format.
I appreciate your answer, thanks.

[ga2p]

Hello, is there any method to generate the widevine license if I already have the kid:key?

[ElCap]

Hello, is there any method to generate the widevine license if I already have the kid:key?

The whole reason for the widevine license request is to get the key, so if you already have the key, what's the point?

[ga2p]

Hello, I use the keys to play directly, some mpd/m3u8 don't have "cenc:default_KID" in the manifest so it doesn't work.
Either I patch the manifest by adding "cenc:default_KID" or I have to pull the widevine license.
So if I already have the key, I thought of generating the widevine license without attacking the original server.
All the best.

[ElCap]

hmmm interesting... so its for the player?
how does having the kid in the manifest affect the key retrieval (without license server)?
theres probably a method to feed the keys to the player directly without it needing to request it externally.

[ga2p]

hmmm interesting... so its for the player?
how does having the kid in the manifest affect the key retrieval (without license server)?
theres probably a method to feed the keys to the player directly without it needing to request it externally.

Yes, the player is OTT Navigator and Tivimate.

These two formats can be used:
#KODIPROP:inputstream.adaptive.manifest_type=mpd
#KODIPROP:inputstream.adaptive.license_type=cleark ey
#KODIPROP:inputstream.adaptive.license_key=72b387a 528f8b4cf79b9fa07a058bbac6:d9441c93cdf8378dc2028a7 72ac9790

or

#KODIPROP:inputstream.adaptive.manifest_type=mpd
#KODIPROP:inputstream.adaptive.license_type=org.w3 .clearkey
#KODIPROP:inputstream.adaptive.license_key={"keys" :[{"kty":"oct","k":"p+Ccb0evVqcvLMmw7y4msg","kid":"J j9tsS1vm+mZt4nrVNMlXQ"}],"type": "temporary"}

Are examples.
If you have the default_KID it works, if not, no.
I read the documentation and I didn't find anything, that's why I thought about generating the widevine license as I already have the kid-key and it's resolved, but I didn't find anything on how to generate it.

[Rathan]

hmmm interesting... so its for the player?
how does having the kid in the manifest affect the key retrieval (without license server)?
theres probably a method to feed the keys to the player directly without it needing to request it externally.

Yes, the player is OTT Navigator and Tivimate.

These two formats can be used:
#KODIPROP:inputstream.adaptive.manifest_type=mpd
#KODIPROP:inputstream.adaptive.license_type=cleark ey
#KODIPROP:inputstream.adaptive.license_key=72b387a 528f8b4cf79b9fa07a058bbac6:d9441c93cdf8378dc2028a7 72ac9790

or

#KODIPROP:inputstream.adaptive.manifest_type=mpd
#KODIPROP:inputstream.adaptive.license_type=org.w3 .clearkey
#KODIPROP:inputstream.adaptive.license_key={"keys" :[{"kty":"oct","k":"p+Ccb0evVqcvLMmw7y4msg","kid":"J j9tsS1vm+mZt4nrVNMlXQ"}],"type": "temporary"}

Are examples.
If you have the default_KID it works, if not, no.
I read the documentation and I didn't find anything, that's why I thought about generating the widevine license as I already have the kid-key and it's resolved, but I didn't find anything on how to generate it.

By entering the ClearKey value in License Type and without the type of license given by the Default KID in the MPD, the player fails to identify the type of license used, so if you can impose with some directive that Widevine must use maybe you can make it work.

Try to consult the documentation to see if you can do something similar:
[{"kty":"oct","k":"","kid":"", "default_kid":""}],"type": "temporary"} or [{"kty":"oct","k":"","kid":""}],"type": "widevine"}