The Two-factor Authentication for your Control Panel login is working with a one-time token delivered by the Google Authenticator APP for Android and iPhone smartphones.
It is available for your CentralNic Reseller account login and can also be set indivdually all users of your account. You can reach the setting via the User menu on the upper right side -> Passwords & Security
Activate it by clicking on "Enable Two-factor Authentication".
After clicking the Control Panel will ask you to install the Google Authenticator App on your phone and scan the shown QR code with your Authenticator APP or enter the secret manually.
When your Two-factor Authentication is properly set up you will be asked to enter the 6 digit code and confirm to activate the two factor authentication.