Wireless Encryption Key Exchange Adapting to RF Interference

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Solution Overview

Problem

Wireless networks with asymmetric computing resources face challenges in securely updating encryption keys due to RF interference and power resets, leading to potential message loss and key synchronization issues between nodes and data concentrators.

Innovation Solution

A method and system for wirelessly exchanging encryption keys that account for RF interference by measuring and adapting transmission attempts, using a key stack with current and static keys, and implementing exception handling to ensure secure key updates even in the presence of interference and power resets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encryption key updates are transmitted wirelessly without compensation for RF interference, then the data processing requirements at wireless nodes remain minimal, but the reliability of key update reception deteriorates due to random interference and RF propagation deterioration

Engineering Contradiction:

Improvereliability of key update receptionVSAvoiddata processing requirements at wireless nodes

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by measuring RF interference levels before attempting key update transmission, and pre-determines the number of transmission attempts based on measured interference conditions. This allows the system to adapt to varying RF conditions without requiring complex real-time decision-making at the resource-constrained wireless nodes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the initiator monitors whether the responder successfully receives and processes key update messages, then adjusts the number of retransmission attempts based on this feedback and current RF interference measurements. This feedback loop improves reliability while keeping node processing simple.

Inventive Principle:

Principle #23Feedback

2Reliability

If the number of transmission attempts is increased to compensate for RF interference, then the reliability of key update reception improves, but the loss of time and energy increases due to repeated transmissions

Engineering Contradiction:

Improveprobability of successful key update receptionVSAvoidtime for key update transmission

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system dynamically adjusts the number of transmission attempts based on measured RF interference conditions rather than using a fixed number of retries. When RF conditions are good, fewer transmissions are needed; when conditions deteriorate, the system increases attempts accordingly. This dynamic adaptation optimizes the balance between reliability and time/energy consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of transmission attempt count based on measured RF interference levels. By monitoring RF conditions and adjusting the number of attempts as a variable parameter rather than a constant, the system adapts to changing environmental conditions to maintain reliable key updates while minimizing unnecessary retransmissions.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If encryption key updates are transmitted with multiple retransmission attempts, then the reliability of key update reception improves, but the use of energy at the data concentrator increases due to repeated transmission and processing

Engineering Contradiction:

Improvesuccess rate of key update deliveryVSAvoidenergy consumption at data concentrator

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The data concentrator performs preliminary measurement of RF interference conditions before initiating key update transmissions. Based on this preliminary assessment, it determines the appropriate number of transmission attempts in advance, avoiding unnecessary energy expenditure on excessive retransmissions while ensuring sufficient attempts are made to achieve reliable delivery.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the responder acknowledging successful key update reception to stop further transmissions. This feedback mechanism prevents the data concentrator from continuing to expend energy on retransmissions once the key update has been successfully delivered, optimizing energy usage while maintaining high delivery reliability.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3487117B1Encryption key exchange with compensation for radio-frequency interference

Publication Date: 2021.01.06 SIMMONDS PRECISION PRODUCTS INC

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AI summary

A wireless system and method includes an initiator and a responder. The initiator includes a first transceiver and is configured to generate a new encryption key (52). The responder includes a second transceiver and is configured to communicate wirelessly with the initiator via the second transceiver. The initiator is further configured to measure a radio-frequency interference at the first transceiver (54) and determine an iteration number based upon the radio-frequency interference (56), and transmit a key update message encrypted with a current encryption key that includes the new encryption key to the wireless responder (58). The initiator is also configured to resend the key update message the iteration number of times if the initiator did not receive an acknowledgement from the responder (58, 60,62).