Distributed Group Key Management for Resilient Device Networks

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Solution Overview

Problem

Existing broadcast encryption schemes rely on a central authority to manage and distribute keys within a group of devices, making it difficult for devices to securely manage group membership and send messages without a central authority, and they lack resilience against collusion attacks.

Innovation Solution

Devices within the group can autonomously manage key setup and membership changes, allowing any member to securely send messages to all or subsets of the group without non-addressed members or outsiders decrypting them, by establishing secure connections and using one-way functions to generate and distribute new keys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a central authority is used to manage and distribute keys, then key management is simplified, but system complexity increases and resilience against collusion attacks decreases

Engineering Contradiction:

Improvekey managementVSAvoidsystem complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the central authority from the system and replaces it with a distributed key management mechanism where group members collectively manage keys through cryptographic protocols, eliminating the need for a central authority while maintaining key management functionality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system enables group members to autonomously manage keys and perform membership operations without external intervention. Devices can join, leave, or communicate within the group using distributed key management protocols that allow self-service operations

Inventive Principle:

Principle #25Self-service

2Extent of automation

If a central authority manages group membership, then membership control is centralized, but the system becomes vulnerable to collusion attacks and loses resilience

Engineering Contradiction:

Improvemembership controlVSAvoidresilience against collusion attacks

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent implements self-service mechanisms where group members collectively control membership operations. When a device joins or leaves the group, remaining members autonomously update keys through distributed protocols, ensuring no single point of failure or collusion vulnerability

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The key management function is segmented across multiple group members rather than concentrated in a single central authority. Each member holds partial key information, and collective operations require coordination among members, making collusion attacks ineffective

Inventive Principle:

Principle #1Segmentation

3Reliability

If devices autonomously manage keys without a central authority, then system resilience improves, but key distribution and management complexity increases

Engineering Contradiction:

Improveresilience against collusion attacksVSAvoidkey distribution

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces cryptographic intermediaries in the form of distributed key update protocols. When key changes occur, members use established cryptographic communication channels to securely exchange key material, with the protocol itself acting as the mediator that simplifies the complexity of key distribution

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary key setup and establishes communication protocols before actual key distribution occurs. Pre-configured cryptographic channels and agreed-upon protocols enable members to autonomously manage keys without real-time coordination complexity

Inventive Principle:

Principle #10Preliminary action

4Reliability

If broadcast encryption is used to send messages to subsets of devices, then message confidentiality is achieved, but the system lacks flexibility for dynamic group membership changes

Engineering Contradiction:

Improvemessage confidentialityVSAvoidflexibility for membership changes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic key management that adapts to changing group membership. When devices join or leave, the system dynamically updates key distributions and communication protocols, allowing the broadcast encryption system to maintain confidentiality while adapting to dynamic membership changes

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9948455B2Management of group secrets by group members

Publication Date: 2018.04.17 KONINKLIJKE PHILIPS NV

AI summary

A method of adding a new device (221) to a device group (210), the device group (210, 220) including a plurality of devices, wherein each device in the device group possesses a device group key and device keys of all other devices in the device group for encryption of messages, except its own device key. The method includes: establishing a secure connection between the new device (221) and a first device (211) in the device group (210); sending, by the first device (211) in the device group (210), the device group key and device keys of all other devices (212, 213, . . . , 21N) in the device group (210) to the new device (221); distributing, by one of the other devices (212, 213, . . . , 21N) in the device group (210), the device key of the first device (211) in the device group (210) to the new device (221); generating and distributing, by one of the devices (211, 212, 213, . . . , 21N) in the device group (210), a device key of the new device (221) to all other devices (211, 212, 213, . . . , 21N) in the device group (210). This approach is also generalized to k-resilient schemes.