Segmented Key Distribution for Resource-Constrained Sensor Networks

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Solution Overview

Problem

Resource-constrained wireless sensor nodes in medical sensor networks face challenges in efficiently distributing encryption keys due to high computational costs associated with evaluating polynomials over finite fields, which is essential for secure communication and authentication.

Innovation Solution

The method involves dividing keying material and identifiers into multiple segments, using bivariate polynomials and hash functions, and Merkle trees to enhance security and reduce computational overhead, allowing for efficient key agreement and authentication on resource-constrained devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polynomial evaluation over finite fields is used for key distribution, then security is improved, but computational cost increases

Engineering Contradiction:
ImprovesecurityVSAvoidcomputational cost
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the keying material into multiple shares using secret sharing schemes, where each node receives a portion of the keying material rather than the complete key. This segmentation allows secure key distribution while reducing the computational burden on individual resource-constrained nodes, as they only need to process their specific share rather than performing full polynomial evaluations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a trusted authority or key distribution center as an intermediary that performs the computationally intensive polynomial evaluation and keying material generation. This intermediary handles the heavy computational workload, allowing resource-constrained sensor nodes to participate in secure communications with minimal local computation, thus resolving the contradiction between security and computational cost.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If complete keying material is distributed to each node, then security is improved, but device complexity increases

Engineering Contradiction:
ImprovesecurityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The keying material is segmented into multiple shares distributed to different nodes. Each node stores only its specific share rather than the complete keying material, which reduces the storage and processing complexity at each device while maintaining overall system security through the properties of secret sharing schemes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each node receives and processes only the partial keying material share necessary for its specific communications, rather than receiving or processing all keying material for the entire network. This partial action approach reduces device complexity while sufficient security is maintained for each node's communication needs.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If polynomial degree is increased for higher security, then security is improved, but computational overhead increases

Engineering Contradiction:
ImprovesecurityVSAvoidcomputational overhead
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the high-degree polynomial into multiple lower-degree polynomials through secret sharing. Each node works with a portion of the keying material derived from these segmented polynomials, which reduces the computational overhead at each node while maintaining the security level provided by the original high-degree polynomial structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The trusted authority acts as an intermediary that performs the computationally intensive operations with high-degree polynomials during the key generation phase. The sensor nodes then work with pre-processed, lower-complexity key shares, thereby achieving high security without the computational overhead at the resource-constrained devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2279580B1A method for distributing encryption means
Publication Date: 2019.09.18 PHILIPS INTPROP & STANDARDS GMBH
  • EP2279580B1 patent drawingFigure 1
  • EP2279580B1 patent drawingFigure 2~3
  • EP2279580B1 patent drawingFigure 4~5

AI summary

The present invention relates to method for operating a trust centre for distributing key material to at least one radio station, comprising the steps of at the trust centre, dividing an identifier of the radio station, said identifier being a code word consisting a first number of bits, into a plurality of subidentifiers, and generating for each subidentifier, an keying material function selected out of a set of keying material functions on the basis of the considered subidentifier. at the trust centre, transmitting to the radio station the identifier and the key material comprising the generated encryption functions.