Avionics Message Verification for Decryption Integrity Checks
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Solution Overview
Problem
The frequent changes in decryption algorithms used in avionics systems require repeated certification, which is cumbersome and inefficient, and there is a need for rapid detection of cyber-attacks on these systems.
Innovation Solution
An onboard processing device with a verification module that compares encrypted and decrypted messages to ensure the integrity and behavior of the decryption device, allowing certification of the processing device rather than the decryption device, and enabling rapid detection of cyber-attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the decryption algorithm is changed to adapt to new security requirements, then the security level is improved, but the certification process must be repeated which increases device complexity and time consumption
Solution Approach 1:
The system separates the decryption device from the processing device. The decryption device handles cryptographic operations with its own key management, while the processing device handles verification and control. This segmentation allows the decryption algorithm to be updated in the decryption device without requiring recertification of the entire avionics system, as the processing device's certification remains valid.
Solution Approach 2:
The processing device acts as an intermediary between the decryption device and the external communication infrastructure. It receives encrypted messages, coordinates with the decryption device, verifies decrypted messages against comparison criteria, and manages the overall communication process. This intermediary role allows the decryption device to be replaced or updated without affecting the certified processing logic.
2Reliability
If a new decryption algorithm is implemented to counter new threats, then the security against cyber-attacks is improved, but the certification must be renewed which increases loss of time
Solution Approach 1:
By segmenting the system into decryption and processing functions, the patent enables independent updates of the decryption algorithm in the decryption device without triggering system-wide recertification. The processing device's certification remains valid as it handles verification logic rather than cryptographic operations.
Solution Approach 2:
The system incorporates dynamic algorithm selection capabilities where the decryption device can switch between different decryption algorithms based on security requirements. The processing device verifies decrypted messages using comparison criteria that adapt to different algorithms, allowing the system to evolve security measures without static certification constraints.
3Reliability
If the decryption device is certified to ensure security, then the reliability is improved, but any change in decryption algorithm requires new certification which reduces adaptability
Solution Approach 1:
The patent divides the avionics system into two independently certifiable components: the decryption device and the processing device. The processing device is certified for its verification and control functions, while the decryption device handles cryptographic operations. This allows the decryption algorithm to be changed in the decryption device without requiring recertification of the processing device, thus maintaining both reliability and adaptability.
Solution Approach 2:
The processing device is designed with universal verification capabilities that can handle multiple decryption algorithms through comparison criteria. It verifies decrypted messages by comparing them against expected patterns, message types, or cryptographic signatures without being tied to a specific decryption algorithm, enabling it to work with various algorithms while maintaining its certification.
4Productivity
If regular monitoring and verification of decryption device behavior is implemented, then the detection speed of cyber-attacks is improved, but the device complexity increases
Solution Approach 1:
The processing device continuously monitors the decryption device's behavior by receiving decrypted messages and verifying them against comparison criteria. This feedback mechanism detects anomalies such as incorrect decryption, timing deviations, or abnormal message patterns that may indicate cyber-attacks. The verification process provides real-time security monitoring without requiring complex additional hardware.
Solution Approach 2:
The processing device performs self-verification by comparing decrypted messages against expected criteria without requiring external verification systems. It autonomously checks message integrity, timing, and format, enabling the system to monitor its own security state and detect attacks independently, reducing the need for additional complex verification infrastructure.
Data Source
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AI summary
The present invention relates to an electronic processing device (44) intended to be carried on board an aircraft (30) and comprising: - a first receiving module (50) configured to receive an encrypted message, - a second receiving module (52) configured to receive an associated decrypted message, the decrypted message having been calculated via a decryption algorithm applied to the encrypted message by a decryption device (42), external to the processing device (44), and characterized in that it further comprises a verification module (54) configured to verify a behavior of the decryption device (42) via a comparison between the encrypted message and the associated decrypted message according to a set of comparison criterion(a).