Network Device Watchdog Isolation for Secure Continuous Operation
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Solution Overview
Problem
Industrial networked devices face challenges in maintaining continuous operation and integrity while responding to cyber threats, with traditional cybersecurity measures being insufficient against complex attacks, and managing cryptographic keys on potentially compromised devices.
Innovation Solution
A method using a watchdog timer to selectively disable cybersecurity-relevant functions while maintaining basic operations, combined with regular integrity checks and cryptographic backups, ensures resilience against attacks and preserves essential functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cybersecurity measures (firewalls, intrusion detection systems) are implemented to prevent unauthorized access and detect cyberattacks, then security protection is improved, but the system cannot maintain continuous operation during attacks and the measures are insufficient against complex attacks
Solution Approach 1:
The patent segments cybersecurity functions into two categories: basic operating functions that maintain continuous operation, and cybersecurity-relevant functions that can be blocked during attacks. This segmentation allows the system to preserve essential operations while isolating vulnerable functions, resolving the contradiction between security protection and continuous operation.
Solution Approach 2:
The patent implements dynamic control of cybersecurity functions through a watchdog timer mechanism. The system can transition between different operational states (normal operation, security incident response, recovery) based on detected threats. This dynamic approach enables the system to maintain continuous basic operations while adaptively blocking cybersecurity functions during attacks, then restoring them during recovery phases.
2Reliability
If cryptographic functions are blocked to prevent exposure or misuse of cryptographic keys on compromised devices, then cryptographic security is improved, but the device cannot perform basic secure communication and is isolated from the network
Solution Approach 1:
The patent segments cryptographic functions into critical secure communication capabilities that must be maintained and non-critical cryptographic operations that can be blocked. This selective segmentation allows the device to preserve essential secure communication channels while blocking other cryptographic functions that might be exploited by attackers, resolving the contradiction between cryptographic security and communication capability.
Solution Approach 2:
The patent applies different security measures to different cryptographic functions based on their criticality. Essential secure communication functions maintain full cryptographic capabilities, while less critical functions are blocked or restricted. This local differentiation of security measures allows the system to maintain necessary communication while protecting against cryptographic key exposure.
3Measurement precision
If integrity checks are performed frequently to detect tampering and attacks, then detection capability is improved, but system complexity and processing overhead increase
Solution Approach 1:
The patent implements periodic integrity checks using a watchdog timer that triggers security assessments at predetermined intervals. This periodic approach provides regular detection capability without requiring continuous monitoring, thereby reducing system complexity and processing overhead while maintaining adequate detection precision for security threats.
Data Source
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AI summary
The procedure for operating a network device (IOTD) employs a watchdog timer (AWD) which, upon expiration, disables at least one cybersecurity-relevant operating function (SF) of the network device (IOTD), while maintaining the remaining basic operating functions (BF) of the network device (IOTD). The network device (IOTD) is then subjected to an integrity check, and the watchdog timer (AWD) is reset based on the result of this check. The network system is configured to execute this procedure.