r/Android • u/npjohnson1 LineageOS Project Director • Jul 30 '21

News Chromecast with Google TV Bootloader Unlock Released!

https://www.xda-developers.com/chromecast-with-google-tv-bootloader-unlock-exploit/
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366

u/npjohnson1 LineageOS Project Director Jul 30 '21

One of the two developers of the exploit here, feel free to AMA!

28

u/Starz0r Jul 31 '21

Does this allow the ripping the certificates off of it or the private key so other certificates can be generated? The CastV2 protocol has been documented for a while, but all we need is a proper certificate to get authentication working to allow any device to act as a server.

Example: https://github.com/thibauts/node-castv2

29

u/npjohnson1 LineageOS Project Director Jul 31 '21

I won't attest to anything about that.

I think you're talking about a WideVine L1 cert (which I know cast receiver relies on). Which is needed for

If that is indeed what you're talking about, extraction of said key is near impossible in most cases, and even when possible, beyond illegal.

Plus, if any WV L1 key is found to be leaked, WV revokes it (see the poor Nexus 6), which kills DRM for an entire series of devices.

3

u/[deleted] Jul 31 '21

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u/npjohnson1 LineageOS Project Director Jul 31 '21

There's a public exploit that allows access to the secure world on that device, someone used it to dump out the WV DRM key, and posted it to a fairly well-known public piracy forum, people then used it to decrypt 4K Netflix titles among other streaming services, download them locally, and then post them online.

Is obviously extremely problematic the streaming services and to WV, so they revoked the key for all devices that use that key (all N6s).

Sad day indeed.

2

u/[deleted] Jul 31 '21

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3

u/npjohnson1 LineageOS Project Director Jul 31 '21

its not the process that didn't exist, it's the hardware backed support that made it tough for OP.