AIN based methods and apparatus for authenticating and authorizing people to register information corresponding to a telephone number, e.g., in an ENUM database, are described. The methods of the invention may be used to authenticate a party seeking to register telephone number related information with ENUM. A trigger is set on an ENUM registration line. Calls to the ENUM registration line activate the trigger causing LIDB information corresponding to the calling party number to be retrieved. The retrieved information, e.g., name, address and/or phone number is supplied to an ENUM registration service which returns a password to be used when updating or supplying ENUM registration information corresponding to the phone number from which the registration call is placed at some future time, e.g., via the Internet. Assigned ENUM passwords can be obtained when forgotten by placing a call to the registration service from the registered or associated phone number.