UE Peripheral Key Negotiation via GAA Bootstrap

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Solution Overview

Problem

In the 3GPP Generic Authentication Architecture (GAA), there is a lack of appropriate methods to protect confidential information transferred between peripheral equipment and User Equipment (UE) during network convergence, as subscribers cannot anticipate which equipment will access the UE, making it difficult to implement encrypted information transmission without pre-stored shared keys.

Innovation Solution

A method for negotiating a shared key between the UE and peripheral equipment using the GAA architecture, where the UE calculates a first local interface shared key based on its shared key with the Bootstrapping Server Function (BSF) and the peripheral equipment's identity, and the network side calculates a second shared key, enabling encrypted communication between the UE and peripheral equipment without requiring fixed long-term keys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-stored shared keys are used for encrypted communication between UE and peripheral equipment, then communication security is improved, but device complexity and key management burden increase

Engineering Contradiction:
Improvecommunication securityVSAvoidkey management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The UE autonomously generates the local interface shared key by deriving it from the existing shared key Ks and the peripheral equipment's identity information. This self-service approach eliminates the need for manual key distribution and storage, reducing key management complexity while maintaining communication security through cryptographic derivation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The existing shared key Ks between UE and BSF serves multiple purposes: it not only secures communication with the network but also acts as a root key for deriving local interface shared keys with multiple different peripheral equipments. This multi-functionality reduces the total number of keys needed in the system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If dynamic key negotiation is implemented between UE and peripheral equipment, then adaptability is improved, but communication overhead and processing time increase

Engineering Contradiction:
Improvekey negotiation flexibilityVSAvoidkey negotiation time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The shared key Ks is pre-established between the UE and the BSF through the GBA authentication process before the UE needs to communicate with peripheral equipment. This preliminary key establishment enables rapid derivation of local interface shared keys without requiring time-consuming negotiation protocols at the point of use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The local interface shared key is generated by changing parameters (peripheral equipment identity) from the existing shared key Ks through cryptographic derivation. This parameter-based key derivation provides adaptability for different peripheral equipments while avoiding the overhead of complete key negotiation protocols.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1933498B1Method, system and device for negotiating about cipher key shared by UE and external equipment
Publication Date: 2010.08.11 HUAWEI TECH CO LTD
  • EP1933498B1 patent drawingFigure 1~2
  • EP1933498B1 patent drawingFigure 3
  • EP1933498B1 patent drawingFigure 4

AI summary

A method for negotiating about cipher key shared by UE and external equipment includes: the external equipment transmits the cipher key negotiating request which including the identification of the external equipment to the UE; the UE calculates the first local interface shared cipher key based on the shared key (Ks) between the UE and the BSF and the identification of the external equipment; the network side calculates the second local interface shared cipher key based on the shared key (Ks) between the UE and the BSF, and the obtained identification of the external equipment, then provides the second local interface shared cipher key to the external equipment. A system and device for negotiating about cipher key shared by UE and external equipment.