Relay Protection Command Security via Message Digest Verification
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Solution Overview
Problem
The transmission of relay protection commands over Ethernet is vulnerable to attacks, leading to potential tampering and incorrect actions in substation devices, as conventional security measures are insufficient to ensure the integrity and authenticity of these commands.
Innovation Solution
A method and apparatus that calculate and verify message digests using password information shared between sending and receiving parties, incorporating sending order information with status, sequence, and timestamp, to ensure the integrity and authenticity of protection commands transmitted over Ethernet, thereby preventing tampering and replay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If protection commands are transmitted via Ethernet to reduce cost, then transmission cost is reduced, but security against tampering and replay attacks deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-sharing secret keys between communicating parties before actual command transmission. These pre-established keys are used to generate message authentication codes (MACs) that will verify the authenticity and integrity of future commands, preventing both tampering and replay attacks while maintaining Ethernet's cost advantages
Solution Approach 2:
The patent introduces message authentication codes (MACs) as an intermediary mechanism. These MACs are computed using pre-shared keys and appended to commands, serving as a mediator that verifies command authenticity without requiring changes to the underlying Ethernet transmission infrastructure, thus maintaining cost efficiency while improving security
2Reliability
If message authentication is implemented using pre-shared keys and MACs, then security against tampering is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the authentication mechanism to handle multiple functions: it simultaneously provides tamper detection, replay attack prevention (through sequence numbers), and command verification. This multi-functional approach consolidates security operations into a unified process, reducing overall system complexity despite the enhanced security capabilities
Solution Approach 2:
The patent uses parameter changes by incorporating sequence numbers and timestamps into the authentication process. These parameters dynamically change with each command, enabling the system to distinguish between legitimate sequential commands and replayed attacks without requiring complex cryptographic protocols, thus improving security while maintaining relatively simple device implementation
3Reliability
If sequence numbers and timestamps are added to prevent replay attacks, then security against replay attacks is improved, but data packet size and processing complexity increase
Solution Approach 1:
The patent applies partial action by selectively adding sequence numbers and timestamps only to commands that require replay protection, rather than universally to all data transmissions. This selective approach provides adequate replay attack prevention for critical protection commands while minimizing the overhead and processing complexity for less critical communications
Data Source
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AI summary
The present invention relates to a method and an apparatus for a protection command of transmission relay protection. The apparatus comprises: a calculating module (510), used for calculating a message digest of specified data, the specified data comprising a to-be-sent protection command of relay protection and information about a password that is preset with a receiving party; and a sending module (520), used for sending, to the receiving party through the Ethernet, a packet comprising the protection command and the calculated message digest. By means of the method and the apparatus, the security of protection command transmission through the Ethernet can be enhanced.