Implant Motion Authentication for Secure Medical Device Communication

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Solution Overview

Problem

Existing communication systems between implantable medical devices and external devices lack robust security measures, relying on shared secrets that are vulnerable to breaches and require pre-exchange of keys, posing a risk to patient safety.

Innovation Solution

A system that derives authentication tokens based on motion signals sensed by both the implantable medical device and external device, using synchronized motion signals to generate and align authentication tokens, ensuring secure communication through a private key/public key encryption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-shared keys or cryptographic techniques are used for authentication, then communication security is improved, but device complexity and key management requirements increase

Engineering Contradiction:
Improvecommunication securityVSAvoidauthentication mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses motion sensors in both the implantable medical device and external device to automatically capture motion signals. These signals are processed through synchronized time stamps and cryptographic hashing to generate authentication tokens without requiring manual key exchange or complex key management by the user.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces traditional mechanical key exchange systems with a motion-based authentication system. Motion signals captured by accelerometers or gyroscopes are transformed into cryptographic authentication tokens, substituting physical key distribution with dynamic motion pattern recognition and cryptographic derivation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If pre-shared keys are stored during manufacturing, then authentication is simplified, but security vulnerabilities increase due to potential key breaches

Engineering Contradiction:
Improveauthentication setupVSAvoidsecurity vulnerability
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Instead of static pre-shared keys, the system uses dynamic motion signals captured at the time of authentication. The motion signals are time-stamped and processed through cryptographic functions to generate unique authentication tokens that are valid only for that specific authentication event, making them useless for future attacks.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the authentication parameter from static stored keys to dynamic motion-based tokens. Motion signals are captured, time-stamped, and transformed through cryptographic hashing to create authentication credentials that are both simple to use and secure against breaches.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If motion signals are used for authentication, then security is improved and key exchange is eliminated, but device complexity increases due to synchronized motion signal processing

Engineering Contradiction:
Improveauthentication securityVSAvoidmotion signal synchronization
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system establishes a communication channel first to exchange time stamp information before capturing motion signals. This preliminary synchronization of time references simplifies the subsequent motion signal processing by providing a common temporal framework for both devices to correlate their motion data.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses time stamp information as an intermediary to bridge the motion signal processing between implantable and external devices. The time stamps serve as a reference framework that simplifies the correlation and comparison of motion signals without requiring complex direct synchronization mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If cryptographic techniques are applied to protect data exchange, then communication security is enhanced, but processing overhead and energy consumption increase

Engineering Contradiction:
Improvedata exchange securityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system applies cryptographic techniques selectively - using lightweight cryptographic hashing functions on motion signals and time stamps to generate authentication tokens, rather than applying full cryptographic protocols to all data exchanges. This partial application of cryptography provides adequate security while minimizing energy consumption.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4685811A1System for providing a therapeutic and/or diagnostic function on a patient
Publication Date: 2026.01.28 BIOTRONIK SE & CO KG
  • EP4685811A1 patent drawingFigure 1~2
  • EP4685811A1 patent drawingFigure 3~4
  • EP4685811A1 patent drawingFigure 5~6

AI summary

A system for providing a therapeutic and/or diagnostic function on a patient comprises an implantable medical device having a first implant transceiver circuitry, a second implant transceiver circuitry , an implant processing circuitry and an implant motion sensor. The system furthermore comprises an external device having a first device transceiver circuitry, a device processing circuitry and a device motion sensor. The implant processing circuitry is configured to obtain, using the implant motion sensor and based on a communication established via the first implant transceiver circuitry and the first device transceiver circuitry, a first motion signal and to derive, based on the first motion signal, a first authentication token. The device processing circuitry is configured to obtain, using the device motion sensor and based on said communication established via the first implant transceiver circuitry and the first device transceiver circuitry, a second motion signal and to derive, based on the second motion signal, a second authentication token.