This publication provides a comprehensive guide to achieve secure data-centric interoperability by leveraging Data-Centric Security (DCS) alongside Zero Trust and federated identity frameworks. It documents multinational lessons learned to support the transition from legacy network-centric systems to modern data-centric implementations, detailing the required architectures, policies, and technical mechanisms—such as Attribute-Based Access Control (ABAC) and a dedicated Access Control Framework (ACF)—for ensuring data confidentiality, integrity, and availability. The document introduces the Zero Trust Data Format (ZTDF) for secure object encoding and outlines a structured approach to enabling interoperability across various operational tiers and national systems, while also anticipating updates to integrate emerging technologies and standards for Multi-Level Security (MLS) in Multi-Domain Operations (MDO).