The Digital Credentials for Europe (DC4EU) Large-Scale Pilot focuses on enabling interoperable issuance and verification of digital credentials across Europe, initially in the education and social security domains. It demonstrates how legal, semantic, and technical alignment can be achieved through coordinated governance, common onboarding procedures, and practical interoperability testing, contributing to the broader EUDI Wallet Toolbox ecosystem shared among all LSPs.

Organisational Interoperability

• Implementation of a Collaboration and Cooperation Strategy for multi-stakeholder engagement across Member States and with the eIDAS Expert Group, supporting alignment on policy and technical decisions. → D3.1 Collaboration and Cooperation Strategy v1.0; D3.2 Coordination Report v1.0

• Development of business blueprints for the education, professional-qualifications, and social-security pilots, defining roles, governance models, and operational interfaces between national and sectoral actors. → D5.1 Business Blueprint v2.0; D6.1 Business Blueprint v2.2

• Establishment of an Ecosystem Governance Framework (EGF) and trust-registry model enabling consistent participation, oversight, and onboarding of organisations across domains. → D8.1 Governance Registries and Frameworks v1.0

• Operation of an Interoperability Lab for coordinated testing, community onboarding, and cross-LSP collaboration with EWC, POTENTIAL and NOBID. → D7.3 Interop Lab Guide v1.0; D9.2 Final Report

• Definition of sustainability and ecosystem maturity guidelines to maintain governance structures and cross-domain coordination beyond the pilot phase. → D8.2 Ecosystem Auditing, Certification and Sustainability Guidelines v1.0

Legal Interoperability

• Legal analysis of wallet issuance, PID and attestation onboarding, and operation of EAAs, QEAAs and Pub-EAAs under the eIDAS 2.0 framework → D4.1 Legal Analysis v1.0

• Definition of onboarding, registration, and revocation processes for credential providers, incorporating compliance with ARF 1.4.0 guidance. → D4.2 Onboarding Process Analysis v1.0

• Mapping of regulatory requirements (eIDAS, GDPR, sector-specific law) to pilot operations in education and social-security scenarios. → D5.2 Deployment, Testing and Piloting Scenarios v2.0; D6.1 Business Blueprint v2.2

• Specification of governance and accountability rules for ecosystem participants through the Ecosystem Governance Framework (EGF) and trust-registry model. → D8.1 Governance Registries and Frameworks v1.0

• Integration of compliance, auditing, and certification guidelines to maintain legal trust across Member States. → D8.2 Ecosystem Auditing, Certification and Sustainability Guidelines v1.0

Semantic Interoperability

• Alignment of education credentials with the European Learning Model (ELM), European Qualifications Framework (EQF), and related controlled vocabularies for consistent interpretation across countries. → D5.3 IMAC for Education and Professional Qualifications v2.0

• Definition of common data elements, metadata, and attribute lifecycles (issuance, status, revocation) for PID and attestation providers. → D4.2 Onboarding Process Analysis v1.0

• Description of the IMAC Rulebook and social-security semantics for Portable Document A1 and European Health Insurance Card flows. → D6.3 IMAC – Rulebook and Case Study v1.0

• Establishment of a unified terminology for roles (Issuer, Verifier, Holder, EAA) and attributes, ensuring cross-domain compatibility between the education and social-security pilots. → D5.1 Business Blueprint v2.0; D6.1 Business Blueprint v2.2

Technical Interoperability

• Design and deployment of an Interoperability Lab environment, hosting wallet, issuer and verifier reference implementations for end-to-end testing. → D7.3 Interop Lab Guide v1.0

• Development of an open-source architecture covering credential issuance, verification, revocation, and trust-registry integration. → D7.1 Open-Source Architecture v2.1-1

• Evaluation of tooling and prototype components used during pilots, including test harnesses for cross-implementation validation. → D5.4 Tooling Evaluation Report v1.0; D5.5 Prototype Demonstration v1.0; D5.6 Feedback and Refinement Report v1.0

• Implementation of registries for trust anchors, schemas and revocation lists supporting cross-border credential verification. → D8.1 Governance Registries and Frameworks v1.0

• Definition of post-pilot auditing and sustainability measures ensuring continued interoperability under eIDAS 2.0 and within the evolving EUDI Wallet Toolbox context. → D8.2 Ecosystem Auditing, Certification and Sustainability Guidelines v1.0

Summary

The Digital Credentials for Europe (DC4EU) Large-Scale Pilot demonstrates interoperability through coordinated governance, legal harmonisation, semantic alignment, and technical validation across the education and social-security domains. Its deliverables show that interoperability relies on shared governance structures, consistent regulatory interpretation, common data semantics, and cross-border testing using open-source components and trust registries.

DC4EU highlights:

1. Organisational interoperability through coordinated engagement between Member States, domain authorities, and ecosystem participants, supported by a Collaboration and Cooperation Strategy and an Ecosystem Governance Framework.
2. Legal interoperability by harmonising onboarding, supervision, and liability models for PID and attestation providers under eIDAS 2.0, ensuring compliance with the Architecture & Reference Framework (ARF).
3. Semantic interoperability via the use of the European Learning Model (ELM) and European Qualifications Framework (EQF) in education, and shared data semantics for Portable Document A1 and EHIC credentials in social security.
4. Technical interoperability through the DC4EU Interoperability Lab, open-source issuer and verifier architecture, and registries for trust anchors and schemas supporting cross-border testing and validation.

Notes

Below are selected excerpts from public EWC deliverables that support the interoperability dimensions described above.

• Organisational Interoperability

  • D3.1 Collaboration and Cooperation Strategy v1.0
    “DC4EU establishes a structured collaboration process among Member States and stakeholders to ensure consistency of implementation across domains and alignment with the eIDAS Expert Group.”
    (Section 3 – Governance Approach)

  • D5.1 Business Blueprint v2.0
    “The blueprint describes roles and responsibilities of issuers, verifiers, and relying parties, identifying governance and interoperability requirements to support credential exchange across education systems.”
    (Section 2 – Ecosystem Actors)

  • D8.1 Governance Registries and Frameworks v1.0
    “An Ecosystem Governance Framework (EGF) is defined to organise trust relationships and manage the registration of entities participating in the DC4EU ecosystem.”
    (Page 9 – EGF Overview)

  • D7.3 Interop Lab Guide v1.0
    “The Interoperability Lab acts as a shared test environment where wallet, issuer, and verifier components can be jointly validated.”
    (Section 4 – Testing Setup)

  • D8.2 Ecosystem Auditing, Certification and Sustainability Guidelines v1.0
    “Recommendations are provided to maintain ecosystem governance structures beyond the pilot and ensure long-term sustainability of cross-domain cooperation.”
    (Page 11)

• Legal Interoperability

  • D4.1 Legal Analysis v1.0
    “Legal interoperability is achieved by ensuring that PID, attestation issuance, and verification comply with the requirements of eIDAS 2.0 and associated delegated acts.”
    (Section 4 – Regulatory Context)

  • D4.2 Onboarding Process Analysis v1.0
    “The onboarding process defines registration, supervision, and revocation workflows for issuers and verifiers, following guidance from ARF v1.4.0.”
    (Section 3 – Lifecycle Management)

  • D8.1 Governance Registries and Frameworks v1.0
    “The EGF specifies accountability and supervision mechanisms for Qualified Electronic Attribute Authorities (QEAAs) and their interactions with Wallet providers.”
    (Page 12 – Accountability Model)

  • D8.2 Ecosystem Auditing, Certification and Sustainability Guidelines v1.0
    “A unified auditing and certification scheme supports the mutual recognition of trust across Member States.”
    (Page 7)

• Semantic Interoperability

  • D5.3 IMAC for Education and Professional Qualifications v2.0
    “Education credentials use the European Learning Model (ELM v3.2) and EQF levels to ensure semantic interoperability of learning outcomes and achievements.”
    (Section 5 – Data Model)

  • D6.3 IMAC – Rulebook and Case Study v1.0
    “The Rulebook defines data semantics for Portable Document A1 and European Health Insurance Card credentials, enabling consistent interpretation across countries.”
    (Section 3 – Data Elements)

  • D4.2 Onboarding Process Analysis v1.0
    “Common attribute sets and status metadata are defined for PID and attestation providers to ensure a harmonised lifecycle (issuance, status, revocation).”
    (Section 5 – Attribute Model)

  • D5.1 Business Blueprint v2.0
    “A shared vocabulary for roles (issuer, verifier, holder, EAA) is applied across the education and professional-qualification pilots.”
    (Section 2)

• Technical Interoperability

  • D7.3 Interop Lab Guide v1.0
    “The Interop Lab provides a controlled environment for testing end-to-end credential issuance and verification workflows across implementations.”
    (Section 4 – Environment Setup)

  • D7.1 Open-Source Architecture v2.1-1
    “The DC4EU architecture defines core components (issuance, verification, revocation, trust registry) to support cross-border interoperability in alignment with ARF updates.”
    (Section 2 – Architecture Overview)

  • D5.4 Tooling Evaluation Report v1.0
    “Multiple tools were evaluated to verify compatibility between wallet and verifier implementations.”
    (Section 3 – Tooling Matrix)

  • D5.5 Prototype Demonstration v1.0
    “A working prototype integrates credential issuance and verification workflows using open standards validated through pilot testing.”
    (Page 5 – Demonstration Summary)

  • D8.1 Governance Registries and Frameworks v1.0
    “Registries for trust anchors, schema definitions, and revocation lists are essential to technical interoperability and were implemented as reusable components.”
    (Page 13)