Re:Trying to extract Widewine key: A journey to failure
by nyuszika7h on Sunday August 01, 2021 @05:02PM
(#28029939)
Lately Google has mostly stopped revoking whole devices. Instead, when someone extracts a key from a device and it leaks publicly, they just revoke that one specific device's key. That improves the experience for legitimate users, but also means the person who extracted the key can just go buy another device of the same model and use the same exploit to extract a new working key.
Re:Trying to extract Widewine key: A journey to failure
by grishka on Sunday August 01, 2021 @05:29PM
(#28030179)
Are these keys unique per-device?
Re:Trying to extract Widewine key: A journey to failure
by wmf on Sunday August 01, 2021 @05:36PM
(#28030256)
Yes.
Re:Trying to extract Widewine key: A journey to failure
by baybal2 on Sunday August 01, 2021 @07:14PM
(#28031153)
The content key at most Netflix like website is one for the entire library, only per-device key needed to get that key, and watermark ID is unique.
Re:Trying to extract Widewine key: A journey to failure
by step21 on Sunday August 01, 2021 @12:57PM
(#28027790)
What's L1? web-dls I have seen are always relatively low resolution, so at least it protects fullhd or 4k.
Re:Trying to extract Widewine key: A journey to failure
by nyuszika7h on Sunday August 01, 2021 @02:24PM
(#28028622)
1080p WEB-DLs are very common if you're in the right places, but even public trackers should have plenty. 4K is slightly less common but does also happen, with frequency depending on the streaming service.
Re:Trying to extract Widewine key: A journey to failure
by gruez on Sunday August 01, 2021 @02:25PM
(#28028629)
>so at least it protects fullhd or 4k.
Not really. Popular streaming-exclusive shows often get 1080p versions released within a few hours, and the 2160p versions released within a few days.
Re:Trying to extract Widewine key: A journey to failure
by denkmoon on Sunday August 01, 2021 @09:42PM
(#28032059)
The Grand Tour S04E03 4k web-dl is readily available on private torrent trackers hours after public release on Amazon Prime.
No idea what encryption Amazon use, but suffice to say it is thoroughly broken by someone out there. Given the expense of acquiring those presenters and the production costs of their shows, and how they bring people to the Prime video platform, I suspect Amazon is reasonably interested in keeping that content protected.
Very likely it's not the Shield now which leaks L1, but an actual key recovery because they get the stream even before it gets watermarked in the secure domain.
My guess, it's Qualcomm's debugging TZ applets. They cannot really revoke keys because they will take down a giant amount of Snapdragon based handsets for which manufacturers don't bother to put a single OTA.
This is also likely why Netflix uses such a silly restrictions as refusing to run on old Android version numbers on some Snapdragon handsets, which are easily root bypassable.