Identity Provider (IdP) und Single Sign-On (SSO) in Manufacturing

An Identity Provider (IdP) is a centralized system that manages digital identities, authenticates users, and securely transmits identity information to third-party applications. Single Sign-On (SSO) leverages this central authority to allow users to log in once and gain seamless access to all authorized systems, such as MES, ERP, or cloud portals, without re-entering credentials.

The Architecture of Trust: Why Industry Must Rethink Identity

In traditional manufacturing IT, software landscapes grew organically. Every application—from maintenance tools to quality management software—carried its own local user database. The result is a fragmented "Identity Island" landscape. A centralized IdP solves this by decoupling authentication from application logic, serving as the Single Source of Truth. When an employee leaves the company, their access is revoked at a single point, immediately securing the entire ecosystem. In the era of the NIS2 Directive and IEC 62443, this level of centralized control is no longer a luxury but a regulatory necessity for industrial cyber resilience.

Technical Comparison: Standards for Data Exchange

For SSO to function, the IdP and the application must speak the same language. While Microsoft Entra ID (formerly Azure AD) dominates the office, manufacturing requires hybrid scenarios to bridge the gap between IT and OT (Operational Technology).

The "Shared Terminal" Trap: Common Pitfalls in Production

IdP implementation often fails when it ignores shop floor reality. A classic example is the shared operator terminal at a production line. If an SSO concept requires every worker to enter a complex 16-character password, the practical result is that no one logs out, or workers use shared "group accounts" (e.g., "Line_1_Operator") to avoid production delays.

Operational Error: Implementing Multi-Factor Authentication (MFA) via smartphone apps in areas where mobile phones are prohibited (e.g., ATEX explosion-proof zones or cleanrooms).The Solution: Utilize hardware-based tokens or FIDO2 security keys (e.g., NFC-enabled employee badges) linked to the IdP via OIDC. This combines high-level security with "Tap-and-Go" usability that maintains production flow and ensures high operator acceptance.

Practical Scenario: Integrating Legacy OT

A frequent industrial challenge: A new cloud-based analytics tool supports OIDC, but the legacy SCADA system on the line only understands LDAP or local databases. In a Tier A scenario, an Industrial DMZ is utilized. A local "Identity Proxy" mediates between the modern cloud IdP and local legacy systems. This allows you to leverage SSO benefits without replacing expensive PLCs or aging HMIs (Human Machine Interfaces). This approach protects your capital investment while centralizing access logs for audits and security standard compliance.

FAQ: Frequently Asked Questions on Industrial IdP & SSO

1. Do I need SSO if I only have one MES system? Yes. Security increases through the centralized enforcement of password policies and MFA. Furthermore, it simplifies onboarding: new employees are ready to work in the MES as soon as they receive their corporate IT credentials, eliminating the need for administrators to manually create accounts in the MES.

2. What happens to my production if the IdP fails? This is the primary risk (Single Point of Failure). In manufacturing, a High Availability (HA) architecture is mandatory. Critical systems should also have an "Emergency Login" for local administrators, physically secured (e.g., in a safe), to remain operational during a total network failure.

3. Do older machine HMIs even support SSO? Usually not directly. Identity gateways or industrial thin clients can solve this by handling the authentication at the IdP and then passing the user through to the HMI via an automated local login. This maintains the audit trail without overloading legacy hardware.

4. Is LDAP still state-of-the-art for a new project? For pure cloud projects: No, use OIDC. For local infrastructure (Active Directory integration for machine tools), LDAP remains a necessary evil but must be secured using encryption (LDAPS) to prevent the interception of credentials within the internal network.

Strategic Value and ROI

Consolidating identities typically reduces password-related support tickets by 40–50%. In a factory with 500 digitally active employees, this saves hundreds of man-hours annually for the IT department. More importantly, it ensures compliance: during an audit (e.g., TISAX or ISO 27001), you can prove who accessed which process data at what time at the touch of a button. This minimizes the risk of heavy fines and protects the intellectual property (IP) of your unique manufacturing processes.