A user who wants to use this service forwards their calls to the service’s phone number. Validated calls will be forwarded back to the original number and rung through. The PBX/IVR (Private Branch Exchange / Interactive Voice Response) system answering the service’s number invokes a Call Control XML (CCXML) application for call control and initial filtering. Individuals have the ability to set up their own personal whitelist, so the Caller ID (CID) is used in this initial filtering process. If the incoming call isn’t validated by this list, an IVR application is initiated that will conduct some brief interaction with the caller, such as “Enter the number seventeen” or “Enter the sum of two plus three”. Callers who complete this nominal test have shown themselves to be individuals and are passed through. At any point in the IVR, an override code can be sent (which would be confirmed via a database lookup) allowing any legal automated system to immediately pass through to the caller without taking the IVR test. Three different interfaces (IVR phone menu, smartphone app and web-based) would make it easy to manipulate the whitelist and / or indicate that an unwanted call was just received.