A shared responsibility model to support cross border and cross organizational federation on top of decentralized and self-sovereign identity

This paper discusses the challenges of transitioning from legacy federated identity systems to emerging decentralized identity technologies based on self-sovereign identities (SSI) and verifiable credentials, which are being used in initiatives such as Gaia-X and Catena-X for secure and sovereign data sharing. The adoption of SSI and decentralized identity technologies requires a standardized reference model that addresses challenges around trust in cross-border and cross organizational federations based on decentralized identities. To facilitate this transition, the paper proposes a new Fed2SSI architecture that introduces a middle layer of abstraction for the policy based transformation of credentials, enabling interoperability between legacy federated identity solutions and SSI/decentralized identity environments. The architecture is implemented in a prototype and an exemplary use case is presented to illustrate the added value of this approach.