What is Certificate Management?
Certificate Management is the management of digital certificates used for authentication, encryption and integrity verification within networks and systems. In industrial networks, it is essential for secure communication between, for example, PLCs, SCADA, Remote Access systems and Industrial Firewalls.
Certificates rely on Public Key Infrastructure (PKI) and are essential for trust relationships in modern OT environments.
🧠 How does Certificate Management work?
- Certificate issuance
- A certificate is issued by a Certificate Authority (CA)
- It contains, among others: public key, identity, validity period, algorithms
- Verification and authentication
- Systems check whether the certificate is valid and trusted
- Used in TLS connections, S7 Comm Plus, HTTPS, VPN
- Lifecycle management
- Creating, deploying, revoking, renewing and removing certificates
- Preferably automated or centrally managed
🏭 Use in industrial networks
- Secure communication between PLC and SCADA via OPC UA or S7 Comm Plus
- HTTPS connections to HMI, web servers or Remote Access portals
- Certificate-based authentication in 802.1X with RADIUS
- VPN tunnels between OT sites and management centres
- Use in Zero Trust architectures and SIEM integrations
Without proper certificate management, devices may refuse connections or, conversely, become vulnerable to spoofing.
🔍 Key certificate types
| Certificate type | Use |
|---|---|
| Root CA | Trusted basis for subordinate certificates |
| Intermediate CA | Issuance of certificates within domains |
| Client certificate | Authentication of a device or user |
| Server certificate | Identification of services such as OPC UA or HTTPS |
In OT, it is essential that certificates have long validity, are locally managed and can be rolled out reliably.
🔐 Security considerations
- Implement a local Certificate Authority (CA) in OT networks
- Use strong algorithms (such as SHA-256, RSA-2048+)
- Manage certificates with their validity period and expiry dates in view
- Automate using tools such as:
- Siemens PKI Toolset
- Microsoft AD CS (for internal PKI)
- X.509-based provisioning
- Track certificate changes via audit and Monitoring
- Revocation management (CRL, OCSP) is required when keys are compromised
Outdated or expired certificates can halt processes or isolate network segments.
📌 In summary
Certificate Management ensures secure communication and authentication in OT environments, and prevents data-driven risks from certificate expiry, misconfiguration or Spoofing.