Nexor Protean is a software-defined gateway designed for Defence, Government, Law Enforcement, and Critical National Infrastructure organizations. The product provides policy-enforced data transfer between security domains in cloud, on-premises, and hybrid environments. Built on Nexor's SIXA architecture, Protean operates as a modular platform that performs deep content inspection, malware scanning, and Content Disarm and Reconstruction (CDR) across virtualized and containerised infrastructures. The gateway enforces security policies programmatically and validates software supply-chain provenance through vulnerability scanning and signature verification. The product supports Infrastructure as Code (IaC) and Policy as Code approaches for automated deployment and configuration management. It includes parallel processing capabilities for concurrent file handling and provides a configurable dashboard for monitoring and analytics. Protean performs binary and container image analysis, validates code integrity, and checks software components for authenticity and known vulnerabilities. The system generates comprehensive audit logs exportable to SIEM tools and maintains functional isolation to prevent unauthorized data paths. The architecture is designed to align with UK and NATO security standards, including NCSC guidance for cloud-hosted architectures and ISO 27001 requirements. Deployment options include private clouds, public clouds, and containerised environments with elastic scaling capabilities.