Hi everyone, We are using the App Attest API to securely transition users to our new system. As part of this, we store the Key ID of the attestation key for each user to verify their identity later. However, we’ve noticed that some users are encountering the error “DCErrorInvalidKey 3” when calling generateAssertion. Importantly, the key was previously successfully attested, and generateAssertion has worked before for these users. Our questions: Could this error be caused by an app or iOS update? Is it problematic to link an attestation key's Key ID directly to a user, or are there scenarios where the key might change or become invalid? If there’s a way to mitigate this issue or recover affected users, what best practices would you recommend? Any help or shared experiences would be greatly appreciated! Thanks in advance.

Our business model is to identify Frauds using our advanced AI/ML model. However, in order to do so we need to collect many device information which seems to be ok according to https://developer.apple.com/app-store/user-privacy-and-data-use/ But it's also prohibited to generate a fingerprint, so I need more clarification here. Does it mean I can only use the data to identify that a user if either fraud or not but I cannot generate a fingerprint to identify the device? If so, I can see many SKD in the market that generates Fingerprints like https://fingerprint.com/blog/local-device-fingerprint-ios/ and https://shield.com/?

Our application uses device check api to validate the device token in staging server. We are using "https://api.development.devicecheck.apple.com/v1/validate_device_token"for this.But the response is 500 internal server error. Our production build is working fine.We pointed the build to "https://api.devicecheck.apple.com/v1/validate_device_token" url.We are using the same device check key for both development and production server. Device check was working fine in development server also.Suddenly it started to failed with out making any changes in our code.

Since around March 4, 2025 off and on, we've been receiving 500 errors back from the validate_device_token endpoint on development and production. Today (March 6) we are constantly getting 500 error back. https://api.development.devicecheck.apple.com/v1/validate_device_token This was working previously before then. No change has happened on our end since then. This is a critical piece for our infrastructure. Thanks in advance. -Matt