A method and system for authenticating a telephone number. The method includes receiving a user-inputted telephone number over a communication channel. The method includes providing a security code to a user over the communication channel. The method includes initiating a voice telephone call session to the user-inputted telephone number. The method includes prompting the user over the voice telephone call session. The method includes responsive to receiving the security code from the user over the voice telephone call session, authenticating the user-inputted telephone number.