LAUSR

end-to-end services for individual travelers, traffic management services for smart cities, and services to increase road safety for individual drivers. Figure 1 shows the basic functionality of the Mobility Data Space following the provisions of the International Data Spaces (IDS) Reference Architecture Model (RAM).4 It does not pool data in a central data store but rather connects data providers and data users by the respective use of the IDS Connector component. A catalog allows data providers to present and describe their data resources, together with conditions under which the data can be used. Data users search the catalog for data they need for their smart service. If data demand and supply match, the exchange of the data itself is carried out just between the participants, with no involvement of the in a data space describing the same real-world object. Finally, data spaces can be overlapping and nested so that data holders and data users, respectively, can be participants in multiple data spaces. To implement the European Strategy for Data and create common data spaces, interoperability of data and collaboration of participants is required across the boundaries of individual data spaces. Gaia-X aims to achieve this by providing so-called federation services that function within and across different data spaces. The Gaia-X initiative is organized as a not-for-profit association headquartered in Brussels.c With more than 300 members, the association aims at a federated data architecture that comprises not only data and smart services, but also cloud infrastructure services (see Figure 2). Gaia-X specifies four so-called federation services, namely “identity and trust,” “sovereign data exchange,” “federated catalog,” and “compliance.”3 They form a blueprint for data spaces and allow for “federations of ecosystems,” hence, support interoperability and coordination across data spaces. The latter requires federation of identities of data space participants, of catalog entries, and of data transaction logs.