AKMA Key Delivery for Lawful Interception in Roaming Networks

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Solution Overview

Problem

Existing AKMA roaming solutions do not specify how the home PLMN provides cryptographic parameters to the lawful interception function within the visited PLMN, failing to comply with Lawful Interception (LI) requirements for decrypting encrypted traffic.

Innovation Solution

Implementing an AKMA Anchor Function (AAnF) in the home PLMN to store and manage cryptographic parameters, and deploying a Lawful Interception regulatory control point (ALICP) in the visited PLMN to receive and process these parameters, ensuring compliance with LI requirements by enabling decryption of encrypted traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If AKMA service signaling is used for authentication and key management, then security establishment between UE and AF is improved, but the ability to provide cryptographic parameters to LI function in VPLMN is lost

Engineering Contradiction:

Improvesecurity establishmentVSAvoidcryptographic parameters delivery

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent introduces the AF (Application Function) as an intermediary that receives cryptographic parameters from the AAnF (AKMA Anchor Function) in HPLMN and forwards them to the LI function in VPLMN. This mediator enables the delivery of cryptographic parameters through the VPLMN without compromising the security establishment mechanism.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the cryptographic parameter delivery process into distinct steps: AAnF generates and stores cryptographic parameters, AF receives and processes these parameters, and LI function in VPLMN uses them for decryption. This segmentation allows each component to perform its specific function while maintaining overall system security.

Inventive Principle:

Principle #1Segmentation

2Reliability

If AKMA roaming solution is implemented, then authentication and key management for applications is improved, but compliance with Lawful Interception requirements is worsened

Engineering Contradiction:

Improveauthentication and key managementVSAvoidLawful Interception compliance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The AF serves as an intermediary that bridges the AKMA authentication mechanism and the Lawful Interception requirements. It receives cryptographic parameters from the HPLMN's AAnF and delivers them to the VPLMN's LI function, enabling both authentication security and LI compliance simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The AAnF performs preliminary action by generating and storing cryptographic parameters before the actual communication occurs. These pre-generated parameters are then made available to the AF, which can forward them to the LI function, ensuring that all necessary security and compliance requirements are met before traffic encryption begins.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP4606143B1Key management for applications

Publication Date: 2026.01.28 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Figure 1A~1B
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AI summary

A method (600) for providing cryptographic information to a lawful interception function (LIF) (a.k.a.,. ALICP). The method includes obtaining (s602) an address for the LIF. The method also includes obtaining (s604) cryptographic information (e.g., a cryptographic key) that is used to secure communications between a user equipment (UE) and an application function (AF). The method also includes using (s606) the obtained address for the LIF to provide to the LIF a report message (m518, m524) the obtained cryptographic information.