Testing Europe's Privacy-First Digital Identity in the Real World

Europe's push toward digital identity is reaching a pivotal moment. Member States must roll out European Digital Identity (EUDI) Wallets to their citizens by the end of 2026, after which major online platforms and regulated sectors will be obligated to accept them for authentication. Yet availability and acceptance rules are only the foundation of a working digital identity system.

The deeper questions are more complex: How can individuals demonstrate their identity while keeping personal data private? How can sensitive information move between organizations and across borders while staying under the control of whoever holds it? And as artificial intelligence increasingly demands large datasets, can organizations collaborate on AI training without concentrating sensitive information in single locations?

These challenges sit at the core of Europe's vision for digital sovereignty—using identity and data while maintaining privacy, control and trust. An EU-backed research initiative called TrustED is now testing whether this vision can work outside the laboratory. The project recently gained prominence when CORDIS named it one of 12 featured initiatives in its September Project of the Month selection.

Bridging identity and data sharing

TrustED—Enabling Trustworthy European Data Spaces through Self-Sovereign Identity and Privacy Preserving Technologies—operates under Horizon Europe funding with grant agreement No. 101168467. The project aims to help individuals and organizations extract more value from their data while safeguarding privacy as Europe's data-space framework develops.

This positioning places TrustED at the nexus of two major European policy efforts: the EUDI Wallet initiative and the creation of European data spaces. Merging identity with data sharing introduces fresh dangers. Identity theft and data breaches remain threats, while artificial intelligence compounds the challenge by requiring large volumes of potentially sensitive information for training and analysis. Moving these datasets across organizational and national boundaries raises privacy, compliance and sovereignty concerns.

TrustED tackles these obstacles by merging digital identity with technologies engineered to reduce how much underlying data must be exposed or moved. The consortium includes participants from Spain, Portugal, Italy, Germany and Turkey: Gradiant, InfoCert, Fraunhofer ISST, Fraunhofer AISEC, Tree Technology, CyberSocial Lab, Promptly Health, Sestek, Fundación Cibervoluntarios and Centro Hospitalar e Universitário de Coimbra, with Fondazione Mondo Digitale as an associated partner.

Layering privacy technologies beyond the wallet

At its identity foundation, TrustED incorporates the EUDI Wallet framework, enabling users to demonstrate their identity and exchange verified credentials. The architecture, however, extends much further.

TrustED pairs self-sovereign identity with privacy-enhancing tools: zero-knowledge proofs, homomorphic encryption and differential privacy. Each addresses a facet of the same underlying challenge—verifying information or deriving insights from it while disclosing as little of the raw data as feasible.

A zero-knowledge proof, for instance, permits someone to show that a given condition has been met without divulging all the information supporting that claim. The concept is simple: demonstrate only what must be demonstrated rather than sharing the entire dataset behind it.

TrustED extends this thinking to artificial intelligence through federated learning. Instead of consolidating datasets in a central location to train an AI model, processing happens where data already sits. Organizations can contribute to a collective model while keeping their raw data in place.

This strategy may grow increasingly vital as Europe seeks to balance the economic potential of data and AI against its commitments to privacy and digital sovereignty.

Pilots test the approach with real users

TrustED is validating its technologies through two distinct real-world trials.

In Spain, Fundación Cibervoluntarios engaged more than 70 volunteers of varying ages with the TrustED digital wallet. Participants issued, kept and transmitted verifiable identity and volunteering credentials while researchers tracked their views on usability, security, privacy and trust.

Portugal hosted a second pilot focused on healthcare. Partnering with Centro Hospitalar e Universitário de Coimbra, TrustED tested a federated-learning system for studying and forecasting viral respiratory illnesses, including influenza, COVID-19 and RSV. The design permits institutions to work together on AI models while their underlying clinical data stays decentralized and under their ownership.

Together, these trials examine two dimensions of Europe's digital sovereignty approach: whether citizens can comfortably govern and distribute digital credentials, and whether institutions can gain insights from sensitive data without surrendering control of it.

Privacy-preserving technology may function correctly in principle yet still falter if people lack confidence in it or fail to grasp how it works. Similarly, data sovereignty rings hollow if organizations must ultimately relinquish control of their data to take part in shared analytics.

Moving from rules to operational reality

TrustED's importance stretches beyond its CORDIS recognition. As Europe transitions from EUDI Wallet regulation to actual deployment, the focus is shifting from articulating digital sovereignty to making it function in the field. TrustED is simultaneously testing multiple components of that framework: digital wallets and verifiable credentials for proving identity, privacy-enhancing technologies for limiting what gets disclosed, and federated learning for leveraging sensitive data without centralizing it.

The pilots underscore a vital reality: meeting technical standards alone will not ensure success. Citizens must grasp and have confidence in the controls available to them, while institutions require privacy-preserving tools that operate within genuine operational and regulatory constraints.

The EUDI Wallet could furnish Europe with a dependable identity foundation. Initiatives like TrustED are now examining what follows: whether citizens and organizations can genuinely use identity and data while preserving control over both.