OT Communication Channel Authorization During Authentication Outages
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Solution Overview
Problem
Existing industrial control systems face challenges in maintaining high availability and secure communication when the authentication service becomes unavailable due to hardware or software malfunctions, leading to potential disruptions in the communication between OT devices.
Innovation Solution
The method extends the validity period of tokens used for authorizing logical communication channels beyond their expiration time, allowing OT devices to continue communication even if the authentication service is unavailable, and employs alarm modes to manage token updates when new tokens cannot be provided.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If communication channels are terminated when tokens expire, then security is maintained, but system availability and continuity deteriorate
Solution Approach 1:
The system dynamically adjusts its security validation behavior based on the availability of the authentication service. When the service is available, strict token validation is applied. When the service becomes unavailable, the system transitions to a more lenient mode that accepts expired tokens for already-established communication channels, maintaining adaptability between security and continuity requirements.
Solution Approach 2:
The validation parameters for tokens are changed based on system conditions. Normally, tokens are validated with strict expiration checks. When the authentication service fails, the system changes the validation parameter to accept tokens beyond their expiration time, effectively modifying the security criterion to maintain operational continuity.
2Reliability
If the authentication service is made highly available with redundancy, then availability is improved, but system complexity and cost increase
Solution Approach 1:
The communication channel becomes self-sufficient by maintaining its own authorization state and validation capability independent of the authentication service. Once a token is validated and a channel is established, the channel can continue operating without requiring continuous authentication service intervention, effectively serving itself during service outages.
Solution Approach 2:
The system performs preliminary authentication and channel establishment when the authentication service is available, storing the validation results locally. This preliminary action allows the communication channel to operate autonomously later without requiring continuous service availability, avoiding the need for redundant authentication infrastructure.
Data Source
Figure 1~2
AI summary
A communication method in an industrial control system is described, comprising a first OT device (10) and a second OT device (20), as well as an authentication service (50). Maintaining a communication channel (LCC) established between the OT devices (10, 20) requires the successful authorization of a token with a predefined validity period. The token is generated by the authentication service (50) and provided to the first OT device (10) when the first OT device (10) meets predetermined criteria. If the token is not renewed before its assigned validity period or expiration time, the communication channel (LCC) is terminated.The token is processed by the second OT device (20) for authorization of the logical communication channel (LCC) beyond its validity period or expiry time if the provision of a subsequent token between the first OT device (10) and the authentication service (50) is not possible or fails.