Call Warning System Using SIP Identity Headers

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Solution Overview

Problem

Existing methods for combating special scams, such as 'It's me' telephone scams, are ineffective when attackers frequently change caller numbers, as blacklisting becomes obsolete and fails to provide real-time warnings, especially for international calls.

Innovation Solution

A call warning system that sets an international call identifier in SIP signals relayed across countries, using the 'verstat=No-TN-Validation' identifier in the P-Asserted-Identity header, to warn recipients before answering calls from foreign countries, thereby indicating potential scams without relying on static caller number information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If caller numbers are registered on a blacklist in advance, then scams using known numbers can be blocked, but scams using frequently changed numbers cannot be detected

Engineering Contradiction:

Improvescam detection accuracyVSAvoidability to detect frequently changing scam numbers

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system transitions from static blacklist registration to dynamic real-time detection by analyzing call patterns, answer rates, and international call identifiers. The call warning apparatus continuously monitors and evaluates incoming calls, adapting to new scam patterns without requiring pre-registration of caller numbers.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system performs preliminary analysis of incoming calls by examining international call identifiers and call patterns before the call is fully established. This allows warnings to be issued proactively based on suspicious patterns rather than waiting for confirmed scam numbers to be registered.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If international call identifiers are used to detect foreign scams, then real-time warnings can be issued, but false warnings for legitimate international calls may occur

Engineering Contradiction:

Improvereal-time scam detection speedVSAvoidfalse warning rate

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system uses multiple parameters for evaluation including international call identifiers, caller ID information, answer rates, and call patterns. By analyzing combinations of these parameters rather than relying solely on international call identifiers, the system distinguishes between legitimate international calls and scams more accurately.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system incorporates feedback mechanisms where call outcomes (answered, rejected, no answer) are analyzed to refine detection accuracy. The evaluation information is continuously updated based on actual call patterns, allowing the system to learn and reduce false warnings over time.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12063324B2Call alert device, call alert system, call alert method, and call alert program

Publication Date: 2024.08.13 NIPPON TELEGRAPH & TELEPHONE CORP

AI summary

When an SIP server receives a call signal addressed to a callee side terminal, the SIP server transmits a warning signal to the callee side terminal before transmitting the call signal to the callee side terminal when an international call identifier indicating that the call signal passes through a foreign country is set in the call signal. In addition, when the SIP server receives the call signal addressed to the callee side terminal, the SIP server includes a warning that the caller number is disguised in a warning signal when an international call identifier indicating that the call signal passes through a foreign country is set in the call signal and the caller number of the call signal is a number from a country in which the callee side terminal is located.