ACARS Encryption via Flight Parameter Keys

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Solution Overview

Problem

Current methods lack an efficient way to implement encrypted communications in aircraft line-replaceable units (LRUs) without requiring costly and time-consuming Federal Aviation Administration (FAA) recertification.

Innovation Solution

A method that generates cryptographic keys from flight parameter values to encrypt and decrypt data using existing avionics systems, applying XOR logic, which allows for secure communication without the need for additional hardware or recertification, utilizing multiple layers of encryption corresponding to different LRUs to enhance security and avoid bottlenecks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encrypted communications are implemented in aircraft LRUs using traditional methods, then security is improved, but costly and time-consuming FAA recertification is required

Engineering Contradiction:
Improvecommunication securityVSAvoidrecertification time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the parameter of cryptographic key generation from static/pre-shared keys to dynamic keys derived from flight parameters (altitude, speed, heading, timestamp). This parameter change enables encryption without requiring hardware modifications or FAA recertification, as the encryption system uses existing avionics data streams to generate keys, thereby improving security while avoiding the recertification process entirely

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system enables the aircraft's existing flight management system to automatically generate cryptographic keys using its own flight parameter data (altitude, speed, heading, timestamp). This self-service approach eliminates the need for external key distribution infrastructure or hardware security modules, allowing encrypted communication to be implemented without additional hardware or recertification

Inventive Principle:
Principle #25Self-service

2Reliability

If additional hardware is added to implement encryption, then security is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecommunication securityVSAvoidhardware requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the existing flight management system perform multiple functions: it continues to monitor flight parameters for navigation and control purposes while simultaneously using those same parameters to generate cryptographic keys for secure communication. This multi-functionality eliminates the need for dedicated encryption hardware, reducing device complexity while maintaining security

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

Solution Approach 2:

The aircraft's existing avionics system generates its own cryptographic keys using its operational flight data, eliminating the need for external key management infrastructure, hardware security modules, or additional encryption devices. The system serves its own key generation needs using readily available flight parameters

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If static encryption keys are used, then implementation is simpler, but security is weakened due to predictability

Engineering Contradiction:
Improveimplementation simplicityVSAvoidencryption security
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent transitions from static encryption keys to dynamic keys that change with each flight segment. The cryptographic key is continuously updated based on changing flight parameters (altitude, speed, heading, timestamp), ensuring that even if one key is compromised, it cannot be used to decrypt other communications. This dynamic approach maintains implementation simplicity while dramatically improving security

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system periodically regenerates cryptographic keys based on flight parameter changes and timestamp intervals. This periodic key regeneration ensures that encryption keys remain unpredictable and secure while maintaining a systematic implementation approach that builds upon existing periodic flight data collection

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3136680B1Lightweight cyber secure bi-directional aircraft communications addressing and reporting system (ACARS) transmission
Publication Date: 2018.07.04 THE BOEING CO
  • EP3136680B1 patent drawingFigure 1
  • EP3136680B1 patent drawingFigure 2
  • EP3136680B1 patent drawingFigure 3

AI summary

The present invention generally relates to systems and methods for encrypting data. The disclosed techniques can include tracking a plurality of flight parameter values for a plurality of flight parameters of an aircraft, generating a first cryptographic key from the plurality of flight parameter values, encrypting plaintext using the first cryptographic key to generate a first ciphertext, and sending, from a sender to a receiver, a message comprising the first ciphertext.