DE4A has explored and piloted across borders the once-only principle (OOP) for Member States. In this regard, the project has addressed architectural, technical, semantic, legal and organisational barriers to cross border interoperability in the context of EU public administrations modernisation (Once-Only Principle (OOP), Single Digital Gateway Once-Only Technical System (SDG OOTS)).
The main results have been the following:
-Hands-on experience and knowledge for DE4A Member States: The project has generated for 8 participating Member States (also Germany who joined as observer for an additional pilot with The Netherlands and other stakeholders the necessary experience to address short, medium and longer term challenges in the contexts of Once-Only, Single Digital Gateway and effective and integrated cross-border public service delivery to citizens and businesses in the context of public services modernisation across the EU.
-DE4A Multipattern architecture for the cross-border exchange of evidences that comprises the following interaction patterns: Intermediation, User Supported Intermediation (USI), Lookup, Verifiable Credentials, Subscription & Notification and special case of ‘Push’-like pattern linking domicile registration and deregistration procedures. The evidence exchange pattern adopted by the Implementing Regulation on technical specifications for SDG OOTS very clearly matches the DE4A USI pattern. In addition, this flexible architecture can be applied to a much broader range of public sector services, going beyond the principal focus of the SDGR and may be established as a horizontal infrastructure to be used for a multitude of sectoral requirements.
-DE4A connector that is the component that establishes the cross-border communication between the Member States (Data Evaluators that request the evidences and Data Owners that owns the evidences) for the exchange of evidences over an eDelivery network. The connector improves interoperability by supporting multiple patterns in a single application and making easy scalability to connect large numbers of Data Evaluators and Data Owners-
-DE4A Self-Sovereign Identity (SSI) Framework with two main components: the SSI Authority Agent and the Mobile End User Agent. This framework supports the implementation of Verifiable Credentials (a user-centric evidence exchange pattern), following specific project requirements such as re-use of existing legal and technical frameworks and using eID and eIDAS to facilitate the authentication process of the users, as well as using the SSI approach to facilitate the user-centric, evidence management and exchange, aligning with EBSI/ESSIF specifications and integrating with such EU-wide framework and infrastructure through EBSI’s Early Adopters Programme. This framework is relevant for the upcoming EU Digital Identity Wallets ecosystem (revision of eIDAS regulation) as an alternative way to realize Once-Only. The wallet prototype in DE4A can be seen as “a European Passepartout supporting pseudonymous identification and allowing the user to manage the different personas of their human Digital Twin in a privacy-enhancing way”. With relatively low effort, additional “contexts” can be defined in order to support management of different types of credentials in a single wallet.
-DE4A semantic components required for a common understanding to facilitate the cross-border exchange of information between public authorities. DE4A solves the problem of “evidence mapping” by implementing two concepts, the Canonical evidence and the Information Desk under the principles of proportionality, subsidiarity and efficiency and according to the European Interoperability Framework. The concept of canonical evidence is the keystone of these principles, as it provides the grounds for semantic interoperability of cross-border and cross-sector evidence. The Information Desk can be taken as a reference for further developments of the SDGR OOTS as they provide a simpler approach while offering more functionality. In addition, the DE4A semantic results can be useful for the implementation of OOP through the EU Identity Wallet provided by the upcoming revision of the eIDAS Regulation, for the implementation of OOP at national level or at international level beyond the European Union, and for the implementation of the exchange of information in any domain, not only in the public sector.
-Legal insights on the legal challenges for the implementation of the SDG.
DE4A results have been validated through 3 cross-border pilots (Studying Abroad, Doing Business Abroad and Moving Abroad) comprising 7 use cases with 29 combinations between Member States.
