DECT Handset Key Pre-Distribution for Secure Connection

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Solution Overview

Problem

Current DECT systems transmit dialing information unencrypted until encryption is activated, creating a security gap due to the delay in generating a common key during connection setup, which affects user interface performance and is difficult to standardize.

Innovation Solution

A method where a key is generated and agreed between the base and handset during the first connection, using an index assigned by the base, allowing immediate encryption of data transmitted during the second connection, utilizing a default or derived cipher key stored in memory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encryption is activated during connection setup by generating a common key, then security is improved, but connection establishment time increases and user interface performance deteriorates

Engineering Contradiction:
ImprovesecurityVSAvoidconnection establishment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-distributing encryption keys to handsets through distribution cards during manufacturing or initial setup. This allows the key material to be prepared in advance, so that when a connection is established, encryption can be activated immediately without delaying the connection setup process. The key distribution happens beforehand, separate from the connection establishment timeline.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the encryption key distribution process from the connection establishment process. Instead of generating and distributing keys during connection setup, the key material is distributed separately through distribution cards. This segmentation allows both processes to occur independently, eliminating the time conflict between security setup and connection establishment.

Inventive Principle:
Principle #1Segmentation

2Productivity

If dialing information is transmitted before encryption is activated, then user interface performance is maintained, but security is compromised due to unencrypted transmission

Engineering Contradiction:
Improveuser interface performanceVSAvoidsecurity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses preliminary action by providing handsets with pre-distributed encryption keys before they are needed for communication. This allows encryption to be activated immediately when dialing information needs to be transmitted, eliminating the security gap. The key material is prepared in advance through distribution cards, enabling immediate encryption without delaying user interface operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces distribution cards as an intermediary mechanism for key delivery. These cards serve as a mediator that provides encryption key material to handsets through separate channels (such as近场通信 or other data transmission interfaces), allowing the key distribution to occur independently from the voice communication path and enabling immediate encryption activation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If connection establishment is blocked until encryption is turned on, then security is improved, but device complexity increases due to complex buffering requirements

Engineering Contradiction:
ImprovesecurityVSAvoidbuffering complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-distributing encryption keys before connection establishment. This eliminates the need to block connection setup or implement complex buffering mechanisms, because the key material is already available when needed. The distribution cards provide keys in advance, allowing both immediate encryption and seamless connection establishment without buffering requirements.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If a common key is generated during connection setup, then encryption is enabled, but the process takes several seconds causing a security gap

Engineering Contradiction:
Improveencryption enablementVSAvoidkey generation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent eliminates key generation time during connection setup by using preliminary key distribution through distribution cards. The encryption key material is provided in advance during manufacturing or initial setup, completely removing the several-second delay associated with generating and distributing keys during connection establishment. This allows immediate encryption activation without time loss.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2443852B1Method for quick and secure transmission of encryption key
Publication Date: 2016.04.06 GIGASET COMMUNICATIONS GMBH
  • EP2443852B1 patent drawingFigure 1
  • EP2443852B1 patent drawingFigure 2~3
  • EP2443852B1 patent drawingFigure 4

AI summary

The invention relates to a method for encoding a connection between a base (2) and a mobile part (1), and a computer program product. The method comprises the steps of: a) generating a key agreed to by the base (2) and the mobile part (1) during a first connection, wherein the key comprises an index assigned by the base during the first connection, and b) using the generated key for a second connection between the base (2) and the mobile part (1), wherein the data to be transferred between the base (2) and the mobile part (1) are identified and encoded using the index assigned to the key. The security of wireless data transfer is thus increased in a simple and low-cost manner.