Just trying to understand the way all this works.....

[theshakez]

Hi,

I'm new to all this & have figured out the basics searching on here but still I don't think I understand it all

So I can successfully decrypt Channel 5 using herokuapp (that's all I can use - python etc.. all crazy to me)

naim2007 (THX!!!) gave me some keys for Channel 4 - All 4 as I can't do that via herokuapp - its not that same apparently.

I'm just confused with some terms. People say "need a working CDM"

Is herokuapp a working CDM?

I hear people talking of L3 keys - So is a working CDM someone who has managed to extract a key & they keep it to themselves as otherwise it gets abused / blacklisted?

I missed out on that widevinedecypter ext so never saw that in action. Was that someone who managed to extract the key from the Chrome CDM?

Just want help understanding the process really, sorry if these questions sound stupid.

Cheers, Gaz

[T33V33]

So firstly a CDM is a 'Content Decryption Module' used for decrypting Widevine protected content... Google Chrome has one (ChromeCDM) and android devices have one (AndroidCDM).

The L3, L1 etc is the different security levels, L3 being the least secure. Generally speaking (but not exclusivly) L3 is used for lower quality content and L1 for higher quality

Previously it was possible to get decyption keys using a Chrome addon (widevinedecypter) that used an exploit in ChormeCDM... this was fixed by Google so no longer works.

AndroidCDMs need to be dumped from the device using a script. Currently the scripts publically available can only dump L3... L1 is locked away much better and only a select few have the ability to dump them (and they're not likely to share their methods). Once you dump a CDM it should not be shared as any made public are revoked by Google prety quickly.

Once they have their own personal CDM people are using various scripts combined with an AndroidCDM to spoof licence requests and get the decryption keys... The herokuapp site is just an online script that probably used a CDM stored somewhere to do the work. Other scripts are stored and run locally on a users computer using their own CDM

[theshakez]

Hi Mate,

Cheers for that, good explaining.
Again though, may sound daft.
So is a Chrome CDM "unique"?
I mean, is mine the same as yours or are they individual to each PC that has chrome installed?
Also is CDM just a fancy word meaning "Key" that has been extracted?

Cheers again,

Gaz

[T33V33]

Hi Mate,

Cheers for that, good explaining.
Again though, may sound daft.
So is a Chrome CDM "unique"?
I mean, is mine the same as yours or are they individual to each PC that has chrome installed?
Also is CDM just a fancy word meaning "Key" that has been extracted?

Cheers again,

Gaz

ChromeCDM is not unique... its a dll file included when you download Chrome. Everyone downloads the same file. The old, exploited ChromeCDM is revoked and replaced with the current one in the latest versions of Chrome. Trying to use a old version of Chrome or trying to use the old revoled dll, Widevine content will not play.

There are different 'keys'...
Basically, media gets encrypted usting a key... This key is then locked on a server... The CDM is like a key that allows us to unlock the decryption key from the server. This decryption key is then used to decryp the media.

[karapuz]

trying to use the old revoled dll, Widevine content will not play.

[Attachment 62893 - Click to enlarge]

Screenshot_2022-01-08

[lomero]

@karapuz
not possible that.
only the current cdm 2391 works, the previous one has been revoked.
if you replace new cdm with old video can't play.
If you play the video has no DRM

[theshakez]

Hi Mate,

Cheers for that, good explaining.
Again though, may sound daft.
So is a Chrome CDM "unique"?
I mean, is mine the same as yours or are they individual to each PC that has chrome installed?
Also is CDM just a fancy word meaning "Key" that has been extracted?

Cheers again,

Gaz

ChromeCDM is not unique... its a dll file included when you download Chrome. Everyone downloads the same file. The old, exploited ChromeCDM is revoked and replaced with the current one in the latest versions of Chrome. Trying to use a old version of Chrome or trying to use the old revoled dll, Widevine content will not play.

There are different 'keys'...
Basically, media gets encrypted usting a key... This key is then locked on a server... The CDM is like a key that allows us to unlock the decryption key from the server. This decryption key is then used to decryp the media.

Thanks again for you're reply mate, very helpfull
I just noticed it was yourself who replied on my other thread:

-----------------------------------------------------------

10th Jan 2022 11:01#9
T33V33 T33V33 is offline
Member
Nov 2021
UK
Search PM
All4 is far more complicated than my5. All4 requires extra data in the form of json tokens etc and I don't believe that can currently be done with herokuapp.

Also... All4 mpd's are time sensitive. They expire after a few minutes

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So what you mention above, it that something I could do myself with some extra tools for All 4, or only something you pros can do?

Cheers Gaz

[T33V33]

So what you mention above, it that something I could do myself with some extra tools for All 4, or only something you pros can do?

Anyone can do it... requires the knowlege in writing a script to make the json call and deal correctly with the response.

...But don't get me wrong... I'm no pro... its not something I can do myself as I don't know enough

[karapuz]

only the current cdm 2391 works, the previous one has been revoked.
if you replace new cdm with old video can't play.

https://35mm.online/en/vod/feature-films/the-knave-of-spades/

[lomero]

no. if you play a video with old browser with old cdm, video can't play.
need to update cdm to play video. and with new cdm guesser not work.

THIS IS A FAKE NEWS, DON'T WASTE YOUR TIME ON TRIAL
try myself and not work. stop
(maybe work to some site but this is a very rare event)

[karapuz]

(maybe work to some site but this is a very rare event)

Google Chrome 97.0.4692.71 (x64)

https://files.videohelp.com/u/298918/widevinecdm.dll

https://35mm.online/en/vod/feature-films/the-knave-of-spades/

[zackmark29]

only the current cdm 2391 works, the previous one has been revoked.
if you replace new cdm with old video can't play.

https://35mm.online/en/vod/feature-films/the-knave-of-spades/

LOL! did you used time machine? =D

[theshakez]

So what you mention above, it that something I could do myself with some extra tools for All 4, or only something you pros can do?

Anyone can do it... requires the knowlege in writing a script to make the json call and deal correctly with the response.

...But don't get me wrong... I'm no pro... its not something I can do myself as I don't know enough

Cheers for the info.
If this is something you cant do then I'm not gonna waste my time trying lol.
People seem happy to help here so will just request keys I need.

Cheers.

[rajhlinux]

So firstly a CDM is a 'Content Decryption Module' used for decrypting Widevine protected content... Google Chrome has one (ChromeCDM) and android devices have one (AndroidCDM).

The L3, L1 etc is the different security levels, L3 being the least secure. Generally speaking (but not exclusivly) L3 is used for lower quality content and L1 for higher quality

Previously it was possible to get decyption keys using a Chrome addon (widevinedecypter) that used an exploit in ChormeCDM... this was fixed by Google so no longer works.

AndroidCDMs need to be dumped from the device using a script. Currently the scripts publically available can only dump L3... L1 is locked away much better and only a select few have the ability to dump them (and they're not likely to share their methods). Once you dump a CDM it should not be shared as any made public are revoked by Google prety quickly.

Once they have their own personal CDM people are using various scripts combined with an AndroidCDM to spoof licence requests and get the decryption keys... The herokuapp site is just an online script that probably used a CDM stored somewhere to do the work. Other scripts are stored and run locally on a users computer using their own CDM

Finally a good explanation... I thought "L3" and "L1" was the networking OSI's layer 1 and layer 3 protocol stuff... lol.

Getting the decryption keys is difficult to obtain. Udemy DRM videos doesn't work with the previous widevine on chrome... I guess we have to wait until a tool is made which can bypass DRM easily for few years until a much secure DRM protocol is made or just learn how to reverse engineer this whole DRM stuff which isn't worth the time.