We are having trouble with App Attest when built with different processors. We need to build an IPA to send to our testers. When the app is built using Intel processor, everything works. But when we built using a mac with processor M, them the App Attest process fails.
The error occurs in our backend while validating the attesation object. We are doing the validation as stated by this documentation: https://developer.apple.com/documentation/devicecheck/attestation-object-validation-guide
The process of validating the Attesation Object fails in the step 4, this one:
Obtain the value of the credCert extension with OID 1.2.840.113635.100.8.2, which is a DER-encoded ASN.1 sequence. Decode the sequence and extract the single octet string that it contains. Verify that the string equals nonce.
The problem is that the validation fails only when the app is built in a M processor machine.
In our server we do (using GO Lang) something like this:
if !bytes.Equal(nonce[:], unMarshalledCredCert.Bytes) {
// error
}
unMarshalledCredCert is the nonce extracted from the Attesation Object sent by the mobile application and nonce[:] is the nonce stored in our backend side cache.
What can this be?