Security Architect – OT / Network / PKI Energy Sector | Critical Infrastructure | Hybrid (Australia) The Role A major critical infrastructure organisation is seeking a Security Architect to lead the design and implementation of security across complex Operational Technology (OT) environments. This is a hands-on architecture role, responsible for securing live environments across network, identity, and PKI domains — not a governance-only position. You'll play a key role in a large-scale cyber uplift program, shaping how security is implemented across OT systems that underpin essential services. Key Responsibilities Design and deliver end-to-end OT security architecture Develop High-Level and Low-Level Designs (HLD/LLD) across key platforms Lead network segmentation and firewall architecture (IEC 62443 aligned) Own PKI architecture (CA hierarchy, HSM integration, certificate lifecycle) Implement and govern NAC solutions (Cisco ISE / Aruba ClearPass) Translate AESCSF, SOCI Act, IEC 62443 into enforceable technical controls Contribute to OT SIEM and detection capability (e.g. Microsoft Sentinel) Provide technical leadership and risk input to senior stakeholders About You Essential Experience 8 years in cyber security / network security architecture Strong experience in OT / ICS or critical infrastructure environments Proven delivery of complex architecture artefacts (HLD, LLD, threat models) Deep expertise in: Network segmentation & firewall design PKI architecture and certificate lifecycle management NAC implementation (802.1X, profiling, policy enforcement) Experience with OT protocols (e.g. SCADA, DNP3, IEC 61850, Modbus) Regulatory Experience Exposure to Australian frameworks such as: AESCSF SOCI Act Essential Eight Desirable Microsoft Sentinel / Defender for IoT Azure (ExpressRoute, Arc, Private Endpoints) HSM technologies (e.g. Thales) Energy sector experience The ability to successfully obtain baseline security clearance Why Apply Work on systems of national significance Join a major cyber uplift program with real investment High-impact role with visibility across executive and regulatory stakeholders Exposure to real-world OT environments (substations, control systems) Long-term opportunity in a critical infrastructure domain If you have what we are looking for and are looking for your next engagement, APPLY NOW.