Secure Parameter Protocol for Rotating Code Synchronization

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Solution Overview

Problem

Network communication devices face challenges in maintaining secure communication when entering sleep mode, as they become unsynchronized with rotating codes, and existing protocols may not allow for different codes between secure channels, making them vulnerable to tampering.

Innovation Solution

Implementing a secure parameter protocol that verifies and agrees on a set of secure parameters, such as DSP channel parameters and previous rotating code values, before a network communication device enters sleep mode, allowing synchronization upon waking up using these stored parameters to encode and decode the current rotating code.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a network communication device enters sleep mode to reduce power consumption, then energy efficiency is improved, but the device becomes unsynchronized with rotating codes making secure communication vulnerable

Engineering Contradiction:
Improvepower consumptionVSAvoidsecure communication synchronization
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The secure parameters protocol is executed before the device enters sleep mode to pre-verify and store secure parameters (including previous rotating code values and DSP channel parameters). This preliminary action ensures that when the device wakes up, it can immediately resynchronize with the rotating code using the pre-stored parameters without being vulnerable to tampering during the sleep period.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces secure parameters (comprising previous rotating code values and DSP channel parameters) as an intermediary mechanism. These parameters act as a bridge that allows the device to maintain secure communication capability during sleep mode by enabling reconstruction of the current rotating code state after waking, thus mediating between power savings and security synchronization.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a rotating code is used to prevent tampering with secure communication, then security is improved, but the device cannot enter sleep mode without losing synchronization

Engineering Contradiction:
Improvesecurity against tamperingVSAvoidability to enter sleep mode
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

Before entering sleep mode, the device executes the secure parameters protocol to verify and store the necessary parameters (previous rotating code values and DSP channel parameters). This preliminary preparation enables the device to maintain security while sleeping by having all necessary information to resynchronize upon waking.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent makes the secure communication system dynamic by allowing the rotation of codes to continue during sleep mode while the device remains inactive. The stored secure parameters enable the device to adapt to the rotated code state after waking, thus maintaining security while enabling sleep functionality.

Inventive Principle:
Principle #15Dynamics

3Reliability

If secure parameters are stored for synchronization upon waking, then re-synchronization is improved, but device complexity increases

Engineering Contradiction:
Improvere-synchronization capabilityVSAvoidprotocol implementation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stored secure parameters serve multiple functions: they verify agreement between devices, enable reconstruction of rotating code state, and provide synchronization upon waking. This multi-functionality reduces the need for separate mechanisms for each function, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the state of secure parameters from transient to stored/persistent, allowing them to be reused across sleep cycles. This parameter change enables reliable re-synchronization without requiring complex real-time verification protocols upon waking, thus limiting complexity increase.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3471367B1Verification of secure parameters for rotating codes
Publication Date: 2020.04.22 NXP BV
  • EP3471367B1 patent drawingFigure 1
  • EP3471367B1 patent drawingFigure 2
  • EP3471367B1 patent drawingFigure 3

AI summary

An example network communication device includes a communication circuit and a processing circuit. The communication circuit securely communicates over a network using a rotating code and the processing circuit enter a sleep mode at which time values of the rotating code are unknown by the network communication device. The processing circuit enters the sleep mode by requesting another network communication device of the network to authorize entering the sleep mode, and entering the sleep mode responsive to an indication verifying that the network communication device and the other network communication device agree on a set of secure parameters that is created pseudo-randomly, wherein the processing circuit enters the sleep mode with the set of secure parameters as stored for awakening but without storage of the values of the rotating key.