3 ms·

Is it just the unlocking or do those apps also look at the exact keys securing the boot chain & OS? In other words, what if I install GrapheneOS and lock the bo

Is it just the unlocking or do those apps also look at the exact keys securing the boot chain & OS? In other words, what if I install GrapheneOS and lock the bootloader again?

flutas 2y ago
I've personally looked into the Pixel Screenshots check. It appears that they are doing server side verification of the devices TEE[1] keys plus bootloader checks, either of which will trip it. This can be spoofed using leaked keys (that get revoked fairly quick), but in this case it seems they are also verifying that the keys are the keys for their Pixel 9 devices. [1]: https://source.android.com/docs/security/features/trusty https://source.android.com/docs/security/features/trusty
- privacyking 2y ago
  On a tangent, have you ever looked into the google phone app and how it decides whether it will offer call screening?
DownrightNifty 2y ago
I took a brief look into it, and they use the Google Private Compute Services Protected Download API to download the Gemini Nano model, which uses remote attestation to cryptographically ensure that your device is running the stock ROM: https://github.com/google/private-compute-services/tree/master/src/com/google/android/as/oss/pd https://github.com/google/private-compute-services/tree/mast... I'm not sure why they do that, tbh, since Gemini Nano is now part of Chrome, and you can download it without remote attestation. If you were dedicated enough, you could probably force the AICore system app on a rooted device into using the Gemini Nano model you downloaded from Chrome. I briefly attempted this but it proved too annoying so I gave up. Edit: It appears Pixel Screenshots works differently than Pixel Recorder, which is what I was looking into. https://news.ycombinator.com/item?id=41373011 https://news.ycombinator.com/item?id=41373011

3 ms·

Is it just the unlocking or do those apps also look at the exact keys securing the boot chain & OS? In other words, what if I install GrapheneOS and lock the bo

by codethief 2y ago

Is it just the unlocking or do those apps also look at the exact keys securing the boot chain & OS? In other words, what if I install GrapheneOS and lock the bootloader again?

flutas 2y ago
I've personally looked into the Pixel Screenshots check. It appears that they are doing server side verification of the devices TEE[1] keys plus bootloader checks, either of which will trip it. This can be spoofed using leaked keys (that get revoked fairly quick), but in this case it seems they are also verifying that the keys are the keys for their Pixel 9 devices. [1]: https://source.android.com/docs/security/features/trusty https://source.android.com/docs/security/features/trusty
- privacyking 2y ago
  On a tangent, have you ever looked into the google phone app and how it decides whether it will offer call screening?
DownrightNifty 2y ago
I took a brief look into it, and they use the Google Private Compute Services Protected Download API to download the Gemini Nano model, which uses remote attestation to cryptographically ensure that your device is running the stock ROM: https://github.com/google/private-compute-services/tree/master/src/com/google/android/as/oss/pd https://github.com/google/private-compute-services/tree/mast... I'm not sure why they do that, tbh, since Gemini Nano is now part of Chrome, and you can download it without remote attestation. If you were dedicated enough, you could probably force the AICore system app on a rooted device into using the Gemini Nano model you downloaded from Chrome. I briefly attempted this but it proved too annoying so I gave up. Edit: It appears Pixel Screenshots works differently than Pixel Recorder, which is what I was looking into. https://news.ycombinator.com/item?id=41373011 https://news.ycombinator.com/item?id=41373011