Lightweight Key Update Mechanism for Wireless Sensor Networks

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Solution Overview

Problem

In resource-constrained IoT sensor networks, existing security mechanisms are inefficient and insecure due to the need for manual network key updates and the inability to quickly remove compromised nodes without significant intervention from the network manager.

Innovation Solution

A network manager system that uses polynomial functions to efficiently refresh network keys and blacklist compromised nodes using Shamir's Secret Sharing algorithm, allowing for fast and lightweight key updates and node removal without explicitly identifying compromised nodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual network key updates are used in sensor networks, then security can be maintained, but the system becomes inefficient and requires significant intervention from the network manager

Engineering Contradiction:
ImprovesecurityVSAvoidkey update efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements automatic key update mechanisms where sensor nodes autonomously generate and update their cryptographic keys using polynomial-based secret sharing schemes. The system enables self-service by allowing nodes to participate in key management without requiring manual intervention from the network manager, thus improving productivity while maintaining security through mathematical guarantees of the secret sharing protocol

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent pre-distributes polynomial shares to sensor nodes during network initialization. These preliminary distributed shares enable nodes to automatically reconstruct and update network keys when needed, eliminating the need for manual key distribution and updates later. This preliminary action establishes the foundation for efficient automated key management while preserving security

Inventive Principle:
Principle #10Preliminary action

2Reliability

If compromised nodes are removed from the network, then security is improved, but the process requires significant intervention from the network manager

Engineering Contradiction:
ImprovesecurityVSAvoidnode removal complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts compromised nodes from the network by revoking their access to the secret sharing polynomial. When a node is identified as compromised, the system can exclude it from future key reconstruction without requiring manual reconfiguration of the entire network. The mathematical structure of the secret sharing scheme naturally handles node removal by simply excluding the compromised node's share from the reconstruction process

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements dynamic node membership in the secret sharing scheme. Nodes can be added or removed from the network dynamically without requiring complete re-initialization. The system adapts to changing network composition by allowing flexible inclusion and exclusion of nodes in the polynomial-based key management, reducing the complexity of node removal operations

Inventive Principle:
Principle #15Dynamics

3Quantity of substance

If resource-constrained sensor nodes are used, then deployment cost is reduced, but security mechanisms become inefficient

Engineering Contradiction:
Improvenode resource constraintsVSAvoidsecurity mechanism efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent segments the network key into multiple shares distributed across sensor nodes using polynomial-based secret sharing. Each node stores only a small portion of the key material rather than the complete key, reducing memory requirements. The segmentation of cryptographic functions across multiple nodes distributes computational burden, allowing resource-constrained devices to participate in secure key management without requiring high individual processing power

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes polynomial degree as a parameter to balance security and resource constraints. By adjusting the degree of the secret sharing polynomial, the system can control the number of shares needed for key reconstruction and the computational complexity of key operations. This parameter adjustment allows optimization for resource-constrained sensor networks while maintaining adequate security levels

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3242437B1Light-weight key update mechanism with blacklisting based on secret sharing algorithm in wireless sensor networks
Publication Date: 2019.11.20 NXP USA INC
  • EP3242437B1 patent drawingFigure 1
  • EP3242437B1 patent drawingFigure 2
  • EP3242437B1 patent drawingFigure 3

AI summary

Various embodiments include a network manager for managing network keys in a network having a plurality of nodes, the device including: a memory; and a processor configured to: determine N nodes to blacklist, wherein N is an integer; select a polynomial function from a plurality of polynomial functions of degree K and wherein the polynomial functions define plurality of secret network keys; generate K-N random abscissa values, wherein none of the random abscissa values are not found in a list of node abscissa values; calculate K-N polynomial function values for the K-N random abscissa values; calculate N polynomial function values for N node abscissa values associated with the N blacklisted nodes; transmit a message to nodes in the network including an indication of the selected polynomial function, the K-N random abscissa values, the N node abscissa values associated with the N blacklisted nodes, the K-N calculated polynomial function values, and the N calculated polynomial function values.