Secure Ad-Hoc Wireless Communication via Authentication Server

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing wireless communication methods face challenges in establishing secure, direct communications between devices in ad-hoc mode, particularly for resource-constrained handheld devices, due to limitations in asymmetric and symmetric cryptography, and the need for pre-shared keys and access to Key Distribution Centers (KDCs).

Innovation Solution

A method utilizing an authentication server to generate and manage symmetric encryption keys for secure ad-hoc communications between wireless devices, allowing them to communicate directly without prior trust and without requiring a subscription or access to a KDC, by leveraging existing trust relationships with the authentication server.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If asymmetric cryptography is used to provide secure communication, then security is improved, but computational complexity and power consumption increase significantly

Engineering Contradiction:
ImprovesecurityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the cryptographic operations by introducing a Key Distribution Center that handles the computationally intensive asymmetric cryptography, while the wireless devices perform only lightweight symmetric cryptography. This division allows security to be maintained through asymmetric key exchange while reducing power consumption during actual communication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a Key Distribution Center as an intermediary that facilitates secure key exchange between wireless devices. The KDC performs the computationally expensive asymmetric cryptographic operations centrally, allowing individual devices to communicate securely using efficient symmetric cryptography without bearing the full computational burden.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If symmetric cryptography is used to provide secure communication, then power consumption is reduced, but pre-shared keys must be distributed securely

Engineering Contradiction:
Improvepower consumptionVSAvoidkey distribution complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent introduces a Key Distribution Center as an intermediary that manages symmetric key distribution. The KDC generates and distributes session keys to authorized devices, eliminating the need for manual pre-shared key configuration and reducing the complexity of key management while maintaining low power consumption through symmetric cryptography.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary authentication and key distribution actions through the Key Distribution Center before actual communication begins. Devices authenticate with the KDC in advance to receive their session keys, so that when communication starts, the key distribution complexity has already been resolved and devices can communicate efficiently.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If ad-hoc mode is used for direct communication, then power consumption and interference are reduced, but establishing secure communication becomes more difficult

Engineering Contradiction:
Improvepower consumptionVSAvoidsecure communication establishment
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent introduces a Key Distribution Center as an intermediary that handles the complexity of secure communication establishment. Even though devices communicate directly in ad-hoc mode, the KDC facilitates the initial authentication and key exchange, allowing devices to quickly establish secure communication without complex peer-to-peer negotiation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary authentication and key distribution through the Key Distribution Center before ad-hoc communication begins. This preliminary action resolves the security establishment complexity in advance, allowing devices to engage in power-efficient direct communication using pre-distributed symmetric keys.

Inventive Principle:
Principle #10Preliminary action

4Length of moving object

If infrastructure mode is used for communication, then long-range communication is enabled, but power consumption and interference increase

Engineering Contradiction:
Improvecommunication rangeVSAvoidpower consumption
Core Design Contradiction:
Length of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent segments the communication function by allowing devices to use infrastructure mode only for initial contact with the Key Distribution Center, then switch to ad-hoc mode for actual data communication. This segmentation enables long-range key distribution while maintaining short-range low-power communication for the bulk of data exchange.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP1997292B1Establishing communications
Publication Date: 2018.11.07 BRITISH TELECOM PLC
  • EP1997292B1 patent drawingFigure 1a~1b
  • EP1997292B1 patent drawingFigure 2
  • EP1997292B1 patent drawingFigure 3

AI summary

A method of establishing direct and secure communication between two wireless communications devices is disclosed. The wireless communications devices each have an existing trust relationship with an authentication server operable to authenticate access to a communication network on the basis of those existing trust relationships. The method comprises: (i) sending a communication request message directly from a first wireless communications device to a second wireless communications device; (ii) operating one of said wireless communication devices to request a symmetric encryption key from an authentication server; (iii) responsive to said request, operating said authentication server to: authenticate said one of said wireless communications devices on the basis of said existing trust relationship; generate said symmetric encryption key on successful authentication of said one of said wireless communications devices; and send said symmetric encryption key to said one of said wireless communications devices; (iv) responsive to receiving said symmetric encryption key, storing said symmetric encryption key at said one of said wireless communications devices and communicating it directly to the other wireless communications device; (v) securing direct communications between said wireless communications devices using said symmetric encryption key.