You don’t need to call the issuer. The NFC chip contains data signed by the issuing country. All you need is a list of trusted country CA’s. You can check if i

You don’t need to call the issuer. The NFC chip contains data signed by the issuing country. All you need is a list of trusted country CA’s. You can check if it’s an original by performing a challenge/response protocol. You can read a public key from the signed data, the private key is not externally accessible. You ask the chip to sign some data with it’s private key and you check against the public key. You can do all this from a mobile phone.