Which nullifies the point of certificates having an expiration date (limited window for exploiting a compromised certificate, possibility of domains changing hands), not the point of validating the signature (tie responsibility for apps to who owned a domain on a specific date, allow third parties to create blacklists of bad developers).
Another option is to allow otherwise-valid signatures after expiration. It’s generally still possible to check them.
That completely nullifies the entire point of signature validations.
How? Expiration doesn’t grant an unauthorized party access to the private key.
There’s zero cryptographic reason to have a signed date at that point.
Which nullifies the point of certificates having an expiration date (limited window for exploiting a compromised certificate, possibility of domains changing hands), not the point of validating the signature (tie responsibility for apps to who owned a domain on a specific date, allow third parties to create blacklists of bad developers).