AF Key Verification for Lawful Interception in Roaming
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Solution Overview
Problem
Existing bootstrapping technologies like GBA and AKMA face challenges in enabling lawful interception of user equipment activities, particularly in roaming scenarios, as they prevent Lawful Interception in the Visited PLMN due to encrypted tunnels and lack a mechanism for verifying the authenticity of shared AF keys.
Innovation Solution
A method is introduced to enable lawful interception by using an AF key provided by the Home PLMN or a third party, verifying its authenticity through parallel cryptographic operations, such as encrypting and decrypting a parameter like GUTI using the AF key, and comparing it with the original parameter to ensure matching integrity values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the application function stores information about the communication partner in its own memory, then the communication partner information can be accessed directly by the application, but the security risk increases because the information is stored outside the secure element
Solution Approach 1:
The system divides information storage into two segments: sensitive data (application identifier, authentication information) is stored in the secure element memory, while non-sensitive data (communication partner information) is stored in the application function's own memory. This segmentation allows the application to access communication partner information directly while maintaining security for sensitive data.
Solution Approach 2:
The secure element acts as an intermediary that provides authenticated access to communication partner information stored in the application function's memory. The secure element verifies the application's identity before allowing access, thus mediating between the application's need for direct access and the security requirement.
2Speed
If the application function stores sensitive information like application identifier and authentication information in its own memory, then access speed improves, but security deteriorates due to potential unauthorized access
Solution Approach 1:
Sensitive information (application identifier, authentication information) is segmented and stored separately in the secure element's memory, while non-sensitive information is stored in the application function's memory. This ensures that even if the application function's memory is compromised, sensitive authentication data remains protected in the secure element.
Solution Approach 2:
Critical security data is extracted from the application function's memory and placed into the secure element's protected memory. This extraction removes the security vulnerability while maintaining the application's ability to function, as the secure element can still provide authenticated access to necessary information.
3Reliability
If a public key infrastructure is implemented for authentication, then security is improved, but the complexity of the system increases due to additional authentication steps
Solution Approach 1:
Public key pairs are generated and stored in advance during application installation. The public key is stored in the application function's memory while the private key remains in the secure element. This preliminary setup eliminates the need for complex real-time key generation and exchange, simplifying the authentication process while maintaining security.
Solution Approach 2:
The public key is copied to the application function's memory, allowing it to be used for authentication without requiring continuous access to the secure element. This copying enables efficient authentication operations while the private key remains securely stored in the secure element.
Data Source
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AI summary
The present invention relates to a method to enable lawful interception of activities of a user equipment UE with an application function AF associated to a bootstrapping technology, said activities using an AF key, while the UE is in a roaming situation with a visited Public Land Mobile Network vPLMN using a Generic Universal Temporary Identifier GUTI, said vPLMN having been provided, for lawful interception purposes, with a said provided application function key by a third party controlling the AF.