Bi-directional Cybersecurity Device for Control Systems
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Solution Overview
Problem
Current cybersecurity solutions for safety-critical control systems, such as avionics, rely on unidirectional data-diodes, which are insufficient for bi-directional communication and fail to provide comprehensive protection against internal and external threats, especially in systems requiring real-time data processing and diverse communication protocols.
Innovation Solution
A bi-directional cybersecurity device that processes messages inline across various interfaces and protocols, including deterministic and non-deterministic networks, using customizable rule-sets for validation, sanitization, and blocking of data, and operates as a bridge or gateway to ensure secure communication between safety-critical control systems and external networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unidirectional data-diodes are used for cybersecurity, then protection against external threats is improved, but bi-directional communication capability deteriorates
Solution Approach 1:
The system segments cybersecurity protection into multiple functional modules: data-diode for unidirectional protection, validation engine for bidirectional validation, and protocol translators for different communication directions. Each module handles specific aspects of security, allowing both unidirectional protection and bidirectional communication to coexist without compromising either function
Solution Approach 2:
A validation engine acts as an intermediary between the data-diode and the bidirectional communication interface. This intermediary validates incoming data from external sources before passing it to the control system, and validates outgoing data before transmission, enabling secure bidirectional communication while maintaining the protective function of the data-diode
2Reliability
If comprehensive data validation is performed on all message traffic, then security against internal and external attacks is improved, but processing time and system latency increase
Solution Approach 1:
The system performs preliminary validation by establishing allowed message patterns, data formats, and protocol rules before actual communication occurs. The validation engine is pre-configured with security policies and validation criteria, enabling it to quickly validate messages against predefined rules rather than performing complex analysis on each message, thus reducing processing time while maintaining comprehensive security
Solution Approach 2:
The validation engine adjusts validation parameters dynamically based on message type, source, and context. For deterministic real-time messages, validation is optimized for speed with simplified checks, while for non-deterministic messages, more comprehensive validation is applied. This parameter adjustment allows comprehensive security validation without uniformly increasing latency across all message types
3Reliability
If byte-by-byte validation of message traffic is implemented, then data integrity is improved, but device complexity increases
Solution Approach 1:
The validation engine applies different validation strictness levels to different parts of the message based on their importance and risk profile. Critical fields such as control commands receive byte-by-byte validation with strict integrity checks, while less critical fields such as status indicators receive simplified validation. This localized quality approach maintains data integrity for critical data while reducing overall system complexity
Solution Approach 2:
The validation engine is designed as a universal component that handles multiple validation functions: format validation, protocol compliance checking, data integrity verification, and security policy enforcement. By consolidating these functions into a single multi-functional engine rather than separate mechanisms for each function, the system achieves comprehensive byte-by-byte validation while managing device complexity through functional integration
Data Source
AI summary
A cyber-security device includes a processor operable to process messages with a data validation rule-set; an external communication interface configured for bi-directional data communication between the processor and external networks or systems; and an internal communication interface configured for bi-directional data communication between the processor and a safety-critical control device, wherein the data received by the processor via either the external or internal communication interface is blocked, sanitized, or passed by the appropriate rule-set, depending on whether the data conform to validation criteria established by the rule-set. The processor analyzes the data, preferably byte-by-byte, with the data in each byte being required to conform to the rule-set validation criteria before being passed from the processor to the appropriate interface.