Calling Party Validation via Dual-Channel Code Verification

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Solution Overview

Problem

Existing voice call authentication methods are vulnerable to spoofing, as they rely on shared secrets that can be intercepted, making it difficult for called parties to verify the authenticity of incoming calls, especially when previous communications have been compromised.

Innovation Solution

A method involving a server that monitors two separate communications paths, one for voice calls and another for data, where a code entered by the call recipient is compared with a shared code, ensuring authenticity by preventing code exposure during the call, thus protecting against spoofing attempts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a shared secret code is used for call authentication, then the called party can verify the calling party's identity, but the system becomes vulnerable to spoofing if previous communications are intercepted

Engineering Contradiction:
Improvecall authentication reliabilityVSAvoidspoofing vulnerability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system generates and shares a secret code between the called party and the network infrastructure before the call occurs. This preliminary code exchange establishes a trusted channel that cannot be compromised during the actual call, preventing spoofing attacks.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The network infrastructure (SMS gateway, signaling system) acts as a trusted intermediary that securely manages the secret code. The called party never directly shares the code with the calling party; instead, the network verifies the code during call setup, eliminating the risk of interception between parties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the code is shared over the same communications path as the voice call, then the authentication process is simpler, but the code becomes vulnerable to interception and spoofing

Engineering Contradiction:
Improveauthentication process simplicityVSAvoidcode interception risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The authentication system separates the code exchange channel from the voice call channel. The secret code is transmitted through a dedicated signaling path (SMS, register-dial-register protocol) independent of the voice communications path, ensuring that even if the voice channel is compromised, the authentication code remains secure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system moves the code exchange from the voice domain to a separate data/signaling dimension. By using SMS or signaling system messages for code transmission rather than voice calls, the authentication occurs in a different communications dimension that is not vulnerable to voice call interception or spoofing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If a verification code is incorporated in the call data, then the called party can identify genuine calls from trusted parties, but the shared secret becomes apparent from intercepted calls

Engineering Contradiction:
Improvetrusted call identificationVSAvoidshared secret exposure
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The network infrastructure serves as a confidential intermediary that holds and verifies the secret code. The code is never exposed in the call data stream between parties; instead, the network silently verifies the code during call setup and only allows genuine calls to proceed, preventing secret exposure while maintaining reliable identification.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3769502B1Calling party validation
Publication Date: 2022.10.12 BRITISH TELECOM PLC
  • EP3769502B1 patent drawingFigure 1
  • EP3769502B1 patent drawingFigure 2
  • EP3769502B1 patent drawingFigure 3

AI summary

In order to confirm that a telephone call received by a network termination (12) on a first connection (16) is from a trusted party (10), the called party connects over a second, independent, connection (17) to a server (15) associated with the trusted party (10) and shares a code with the server (15). That code is then transmitted over the first (connection (16) and, if the connection is genuine, it is intercepted by the server (15) which generates a message over the second connection (17) confirming that the code has been matched. This gives the called party assurance that the call is from a party (10) associated with the trusted server (15). If a rogue caller (20) attempts to call the termination (12), the called party's transmission of the shared code will be routed over the caller's connection (26), which is not associated with the trusted server (15), so no match will be identified by the server (15) and no confirmation is returned over the second connection.