In early 2024, ISO approved the creation of a new International Workshop Agreement project to develop a plan for a new identifier that would uniquely identify media channels and brands. The deliverable of this workshop is a document that provides requirements and recommendations for the structure and governance of Unique Media Identifiers (UMiDs) that are assigned to channels and brands (content publishers). The aim of this unique key is to establish source identity, i. e. a clear connection between outlets and assets belonging to the same content publisher, channel, or brand across platforms, including news media websites and their social media presence. Such an interoperable system of identifiers is crucial to safeguarding the integrity of the online news ecosphere,,which is relevant for every stakeholder and user when publishing, accessing, and managing content online.