This technical proposal describes an automated easy to use cost-effective solution that allows automated and manually-dialed legitimate calls, suppresses illegal robocalls, and can work across landlines, mobile phones, and VoIP. The solution can be resident in homes, mobile apps, or offered via telco service providers. It can be easily developed using hardware, software and communication protocols that exist today
Illegal robocalls are primarily enabled by caller id spoofing technology, but can also occur by non-spoofing illegal methods (stolen cell phones, hijacked smart phones, etc,) as well as unscrupulous Do-Not-Call violators. This approach assumes that caller ID by itself is never reliable, and can be spoofed to virtually any number. It uses a combination of tactics and technologies to determine the validity and handling of calls, and to apply rules whether to block or allow the call to reach the recipient. Call handling varies depending on capabilities of the call endpoints (originating caller and called party).
Techniques include combinations of number categorization (at the receiving end), rule-based handling, phone number validation algorithms, phone number validation service providers, screening, customizable behavior options, and methods to deter future call attempts. Some types of callers can generate an outbound call with a dynamic ANI (from a set of phone numbers they own). The ANI is derived using the recipient’s phone number, private key, and current time so that the recipient can use a static numeric algorithm to assert that the call is not spoofed at the time they receive it. Alternate more dynamic algorithm methods will also be discussed. In effect, this solution turns around the idea of caller ID, so that the same kind of spoofing capabilites can be utilized as a validation mechanism.