Ok, so how does that help with device attestation? If I am an app developer how does it tell me that your OS has not been tempered with or actually that my app has not been tempered with? Are there any cryptographic keys stored in a secure place on the device that the Librem vendor can verify?

> This is extremely misleading.

But it's not. It's an architectural difference between how Google and Apple implemented attestation. Apple stores the generated keys in a secure part on your device and certifies them. The rest is your job as an app developer. And as a user, you do not have your iCloud or iTunes account used for device attestation. In contrast Google and its Play services are an integral part of the attestation workflow.

For Apple it's evident from their docs. As a side note: I do try to learn more about this, because of an incoming project concerning it.

> You can’t rely on your app’s logic to perform security checks on itself because a compromised app can falsify the results. Instead, you use the shared instance of the DCAppAttestService class in your app to create a hardware-based, cryptographic key that uses Apple servers to certify that the key belongs to a valid instance of your app. Then you use the service to cryptographically sign server requests using the certified key. Your app uses these measures to assert its legitimacy with any server requests for sensitive or premium content.

Source: https://developer.apple.com/documentation/devicecheck/establ...