Subscriber Service Validation via SUCI Cleartext to Reduce AMF Traffic

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Solution Overview

Problem

The existing process of decrypting subscription permanent identifiers (SUPI) at access and mobility functions (AMF) in wireless networks leads to excessive network traffic, especially when unauthorized UEs attempt registration.

Innovation Solution

Implementing subscriber service validation using subscription concealed identifier (SUCI) cleartext, where the base station identifies approved UEs based on cleartext routing indicators and public key identifiers within the SUCI, reducing the need for decryption by AMF, AUSF, and UDM.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the AMF decrypts the SUCI to validate UE authorization, then security validation is achieved, but network traffic increases and processing time is extended

Engineering Contradiction:

ImproveUE authorization validationVSAvoidnetwork traffic

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the routing indicator from the SUCI structure and processes it separately at the base station before AMF decryption. This allows the AMF to validate UE authorization based on pre-processed routing information, eliminating the need to decrypt all SUCI messages and reducing network traffic while maintaining security validation reliability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The base station performs preliminary processing of the SUCI by extracting and validating the routing indicator before forwarding to the AMF. This preliminary action filters out unauthorized UEs early in the registration process, reducing the burden on the AMF and minimizing network traffic while ensuring authorization validation is maintained

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the AMF decrypts the SUCI to validate UE authorization, then security validation is achieved, but processing time is extended

Engineering Contradiction:

ImproveUE authorization validationVSAvoidregistration processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The base station performs preliminary validation of the routing indicator extracted from the SUCI before forwarding to the AMF. This preliminary action enables faster initial screening of authorized UEs, reducing the overall registration processing time while the AMF maintains security validation through decryption only when necessary

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the UE validation process into two stages: initial routing indicator validation at the base station and detailed authorization validation at the AMF. This segmentation allows time-critical filtering to occur at the base station, reducing registration processing time, while the AMF performs comprehensive validation only for UEs that pass the initial filter

Inventive Principle:

Principle #1Segmentation

3Quantity of substance

If the base station validates routing indicators in cleartext, then network traffic is reduced, but the ability to validate all UEs is limited

Engineering Contradiction:

Improvenetwork trafficVSAvoidUE authorization validation coverage

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The routing indicator serves as an intermediary element that enables the base station to perform initial UE validation using cleartext information. This intermediary approach allows traffic reduction while maintaining validation coverage, as the routing indicator provides sufficient information for initial screening without requiring full SUCI decryption

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250220559A1Subscriber service validation using SUCI cleartext

Publication Date: 2025.07.03 T MOBILE US INC

AI summary

Subscriber service validation using subscription concealed identifier (SUCI) cleartext is disclosed. When a user equipment (UE) attempts to register with a wireless network, it sends its SUCI which has an encrypted subscription permanent identifier (SUPI), but also a routing indicator in cleartext (unencrypted). This is available to the base station. By formulating a list of routing indicators associated with roaming partners (along with its own routing indicator), the base station is able to identify UEs that should be approved for registration. This precludes the need for the access and mobility function (AMF) to involve the authentication server function (AUSF) and unified data management (UDM) in decrypting the SUPI for unauthorized UEs, thereby reducing network traffic. Identification of the public key, associated with the private key used to encrypt the SUPI, is also within the SUCI in cleartext, and so may be used in place of the routing indicator.