Distributed Time Source Validation for Cyber-Resilient Clocking
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Solution Overview
Problem
Current network technologies for precise timing in wide area networks are not scalable, accurate, or resilient against cyber-attacks, such as GPS clock jamming and spoofing, and lack the capability to compare disparate timing sources effectively.
Innovation Solution
A distributed algorithm and signaling mechanism, Distributed Time Source Validation (DTSV), which enables nodes in a network to detect Mutual Clock Discrepancy (MCD) between local and external clock signals, distribute this information, and validate external sources and paths, allowing for the identification and elimination of faulty or compromised time sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS clock synchronization is used in wide area networks, then time synchronization accuracy is improved, but the system becomes vulnerable to cyber-attacks such as jamming and spoofing
Solution Approach 1:
The patent introduces an intermediary validation mechanism where multiple independent timing sources are compared through a distributed validation process. Instead of directly trusting a single GPS source, the system uses multiple paths and sources as intermediaries to validate each other, detecting discrepancies that indicate cyber-attacks or faults.
Solution Approach 2:
The system segments the timing validation process into multiple independent paths and sources rather than relying on a single centralized GPS source. By dividing the timing infrastructure into multiple discrete, comparable sources, the system can identify and isolate compromised sources without affecting the entire network.
2Device complexity
If a single centralized time source is used, then the system structure is simple, but the system lacks scalability and accuracy for wide area networks
Solution Approach 1:
The patent transitions from a single-dimensional centralized time source model to a multi-dimensional distributed model. By adding the dimension of multiple independent timing sources and multiple validation paths, the system achieves both the simplicity of automated validation and the accuracy required for wide area networks.
Solution Approach 2:
The validation mechanism serves multiple functions simultaneously: it provides time synchronization, validates source integrity, detects cyber-attacks, and identifies faulty paths. This multi-functionality allows the system to maintain simplicity while achieving high accuracy across diverse network conditions.
3Reliability
If multiple timing sources and paths are implemented, then the system can detect faulty sources, but the complexity of validating disparate sources increases
Solution Approach 1:
The system implements continuous feedback loops where timing data from multiple sources is constantly compared and validated. The validation results feed back into the source selection and synchronization process, automatically adjusting to identified faults without requiring complex manual intervention or analysis.
Data Source
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AI summary
A method to provide a cyber attack resistant and fault tolerant precision clocking scheme for wide area critical infrastructure networks through what is called Distributed Time Source Validation, DTSV, is provided, which is a distributed algorithm and signaling mechanism for a network to detect a compromised time source or sources in a multiple master clock system. The method comprises providing a local clock signal, receiving in a node R1 an external clock signal from an external source, C or S1, estimating based on the local clock signal and the external clock signal timing parameters associated with the first node and the external source, comparing the timing parameters to detect any Mutual Clock Discrepancy (MCD) between the first node and the external source, and distributing any detected MCD in the network.