A mobile network based authentication system for authenticating a user's access to a restricted-access account includes an application server and an identification server. The application server is configured to authenticate the user's access to the restricted-access account by transmitting a one-time password to a mobile computing device of the user and confirming that the one-time password has been entered by the user. The identification server communicates with the application server after the application server receives a request from the user to access the restricted-access account and before the application transmits the one-time password to the mobile device, to verify that an attribute of the restricted-access account is linked to a network identification of the mobile computing device.