Substation Recertification for Secure Terminal Authentication
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Solution Overview
Problem
Existing automation systems in electrical energy distribution face challenges when integrating a new control center, as they require updating terminal certificates and root certificate authorities, leading to complexities in maintaining secure communication across devices.
Innovation Solution
The method involves recertifying the public key of the substation by the control center, allowing the use of existing terminal certificates and enabling secure communication without the need for new certificates, with the control center acting as a new root certificate authority, ensuring trustworthiness of previous certificates and enabling encrypted communication among terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a control center is connected to the substation, then secure communication and authentication are improved, but the complexity of certificate management increases due to the need for new certificates and root certificate authority updates
Solution Approach 1:
The substation is pre-configured with a self-signed certificate that it can issue to itself. This preliminary action enables the substation to function as its own certificate authority before the control center is connected, eliminating the need for immediate certificate reissuance when the control center is added later.
Solution Approach 2:
The substation acts as an intermediary certificate authority between the control center and the terminals. It issues certificates to terminals independently and can validate them using its self-signed certificate, serving as a mediator that doesn't require direct involvement of the control center in the certificate validation process.
2Reliability
If terminal certificates are updated to include the control center in the certificate path, then authentication trustworthiness is improved, but the effort and time required for certificate reissuance increases
Solution Approach 1:
The substation pre-issues certificates to terminals with itself as the certificate issuer, establishing a valid certificate path before the control center is connected. This preliminary action ensures that terminals have valid certificates that work immediately without requiring reissuance when the control center is added.
Solution Approach 2:
Instead of having the control center issue certificates to terminals (traditional approach), the substation issues certificates to terminals independently. This inverted approach allows terminals to communicate securely with the substation without requiring control center involvement in the certificate issuance process.
3Ease of operation
If existing terminal certificates are continued to be used after control center connection, then ease of operation is improved, but the completeness of the certificate path with respect to the new root certificate is reduced
Solution Approach 1:
The substation creates a self-signed certificate that serves as a valid root certificate in advance. This preliminary action ensures that the certificate path is complete from the terminal certificate through the substation certificate to a valid root, eliminating the need to update terminal certificates when the control center is connected.
Solution Approach 2:
The substation serves itself as a certificate authority by issuing and signing its own certificate. This self-service capability allows the substation to maintain complete certificate paths for its terminals independently of the control center, enabling terminals to continue using their existing certificates.
Data Source
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AI summary
Method for operating an arrangement comprising a substation and at least one terminal connected thereto. The invention relates, inter alia, to a method for operating an arrangement (10) comprising at least one substation (20, 50) and at least one terminal (30-31, 60-61) connected to the substation (20, 50), wherein, within the framework of the method, the at least one terminal (30-31, 60-61) is equipped with a terminal certificate (EZ30, EZ31, EZ60-EZ61) and a corresponding private key that enables signed data transmission, identifies the substation as the certificate issuer, has a signature of the substation and contains a reference to a public key of the terminal.According to the invention, after a control center (100) is connected to the substation, the control center (100) recertifies the public key of the substation by creating a signed certificate (RZ20, RZ50) for the substation containing the public key of the substation. For the authentication of data that is or is to be transmitted from the at least one terminal device to another terminal device, to the substation and/or to the control center, the terminal device certificate, which identifies the substation as the certificate issuer, is transmitted to the other terminal device, to the substation and/or to the control center, and the receiver-side, i.e., terminal-side, substation-side and/or control center-side, certificate verification of the terminal device certificate and/or the authentication of the data signed with the corresponding private key is carried out on the basis of the recertified public key of the substation.