MOBILE ID : Easy Registration/Log-in Service with Mobile Phone Number Instead of email Address.
Mobile Phone ID Registration Precautions
You can log in only with your mobile phone number, once you have registered with mobile ID.
You will be unable to receive any e-mail once you have registered with mobile phone ID, however, SMS will be sent via mobile phone number.
Mobile Phone ID Login Precautions
If you have already registered with an email address, you will be unable to log in with your mobile phone number.