ACARS Message Verification System Using Statistical and Semantic Analysis

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Solution Overview

Problem

ACARS messages are susceptible to interception and manipulation by pirates, allowing false messages to be sent, posing a risk to aircraft and ground entity communication systems, with existing solutions like FR2898445A1 only addressing security levels and not providing comprehensive protection.

Innovation Solution

A system and method for verifying ACARS messages using a database with attack data, a flight data acquisition module, an auxiliary module for data conversion, a detection module for statistical, grammatical, and semantic analysis, and a protection module to perform protective actions, including blocking malicious messages and alerting the flight crew.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ACARS messages are transmitted without verification, then communication speed and simplicity are maintained, but security and reliability deteriorate due to susceptibility to interception and manipulation

Engineering Contradiction:
Improvemessage securityVSAvoidverification system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary verification actions by acquiring flight data before message transmission, converting it to predetermined formats, and storing expected message patterns in advance. This allows the detection module to compare incoming messages against pre-established criteria, enabling security verification without adding complex real-time processing requirements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The verification system is divided into distinct functional modules: a flight data acquisition module that gathers flight parameters, an auxiliary module that converts data to predetermined formats, a detection module that performs statistical/grammatical/semantic analysis, and a protection module that executes protective actions. This segmentation allows each module to perform its specific function independently, reducing overall system complexity.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If comprehensive verification analysis is performed on all ACARS messages, then detection precision improves, but processing time and system complexity increase

Engineering Contradiction:
Improveattack detection precisionVSAvoidmessage processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The detection module performs three types of analysis (statistical, grammatical, and semantic) but applies them selectively based on the message characteristics and threat level. Not all analysis types are executed for every message, allowing the system to achieve high detection precision when needed while maintaining fast processing for routine messages.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

Different verification methods are applied to different parts of the message based on its content and structure. The system performs statistical analysis on message frequencies, grammatical validation on protocol compliance, and semantic inspection on specific content areas, applying the appropriate level of scrutiny to each aspect rather than uniformly analyzing the entire message.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If real-time flight data acquisition and analysis are implemented, then message verification accuracy improves, but system complexity and computational requirements increase

Engineering Contradiction:
Improvemessage verification accuracyVSAvoiddata processing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The flight data acquisition module serves multiple functions: it collects flight parameters, converts them to predetermined formats, and provides data for both message verification and flight monitoring. This multi-functionality reduces the need for separate dedicated verification systems, thereby reducing overall complexity while maintaining high verification accuracy.

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

4Reliability

If protective actions are taken upon detecting attacks, then system reliability improves, but operational interruptions and message loss may occur

Engineering Contradiction:
Improvecommunication system protectionVSAvoidmessage transmission efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The protection module receives feedback from the detection module about message authenticity and threat levels. Based on this feedback, it selectively executes protective actions such as blocking suspicious messages or alerting the flight crew, rather than uniformly blocking all potentially risky messages. This feedback mechanism ensures protection is applied only when necessary, maintaining message transmission efficiency.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3101820B1System and method for verifying acars messages
Publication Date: 2018.08.29 THE BOEING CO
  • EP3101820B1 patent drawingFigure 1
  • EP3101820B1 patent drawingFigure 2
  • EP3101820B1 patent drawingFigure 3

AI summary

The invention proposes a new device and method for verifying ACARS messages between aircraft and ground entities. The system is implemented within the aircraft systems as a further security method in such a way that the payload is not incremented. The system having: a database; a flight data acquisition module; an auxiliary module; a detection module and a protection module. The detection module performs scanning actions such as a statistical analysis, a grammatical validation and a semantic inspection. Thus, the detection module is able to detect an attack, informing to the protection module to perform a protecting action. The method comprises: providing a database having attack data; gathering real-time flight parameters; converting ACARS messages into a preformatted data; performing scanning actions between the preformatted data and both, the real-time flight parameters and the attack data for detecting an attack; providing an alert in case one of the scanning actions detects an attack.