I'm not aware of the details, but I imagine something very similar to EMV payments.
The only difference is that you need to register your SIM with the service beforehand, using a reasonably secure process. Banks make you use their own MFA before you can enable Mobile ID (and no, it's never over SMS).
The only difference is that you need to register your SIM with the service beforehand, using a reasonably secure process. Banks make you use their own MFA before you can enable Mobile ID (and no, it's never over SMS).