The AARC TREE project officially reached the end of its funding period in February 2026, marking the close of a highly productive chapter in the evolution of Authentication and Authorisation Infrastructure (AAI) for the research and education sector. At the time of writing, the project team is preparing for the final review, scheduled for May 2026.
Building on a decade of AAI innovation
AARC TREE set out to evolve the AARC Blueprint Architecture (BPA), building on its latest version published in 2019 at the end of the previous AARC funding cycle. The AARC BPA is a model for deploying interoperable AAIs in the research sector: it provides patterns to standardise how identities and attributes are handled across different independent organisations, resource providers, and models to ensure that privacy and security practices are followed, enabling organisations and resources to trust each other.
The AARC TREE project focused on evolving the BPA and its interoperability framework, namely the set of guidelines, integrating support for user-centric technologies, expanding the authorisation model to enable access to federated data and services, and consolidating existing capacity to reduce fragmentation and unnecessary duplication across the ecosystem.
A new version of the AARC BPA and a rich set of outputs
All project results were completed as planned and on schedule. The flagship output, the AARC BPA 2025, was released in February 2026. The updated BPA places stronger emphasis on OpenID Connect/OAuth 2.0, token-based access, and more flexible identity management models, offering a base framework for secure cross-infrastructure resource access. It also introduces a functional capability-based model (Identity Management, Collaboration Management, and Service Integration), clarifying responsibilities while preserving the layered architecture. It is already being used as the architectural foundation for the EuroHPC Federated Platform and the European Open Science Cloud (EOSC) and serves as a reference model for related national and international initiatives.
Alongside the BPA, the project delivered three further resources:
- A revamped AARC Policy Development Kit (PDK): streamlined to support smaller communities wishing to deploy AAI solutions aligned with the AARC BPA.
- The AARC Handbook: a living document providing practical guidance on implementing the AARC BPA, along with recommendations for the long-term sustainability of AAIs in the research and education sector.
- The AARC Compliance Assessment Toolkit (CAT): an online validation platform enabling AAI service providers to assess their compliance with AARC Guidelines.
Sustainability beyond the project
The conclusion of funding does not mean the end of the work. Like in the past, the AARC community will continue its activities through the AEGIS group, the AARC Engagement Group for Infrastructures, established in 2019 to ensure the long-term stewardship of AARC outputs. AEGIS is the forum of research and e-infrastructures that operate AAIs following the AARC BPA; its members support, assess, and endorse guidelines for AARC Blueprint Architecture (BPA). Christos Kanellopoulos (GÉANT) and Nicolas Liampotis (GRNET) will continue to lead the technical work and report the updates in AEGIS, while David Groep (Nikhef) and Dave Kelsey (STFC-UKRI) will continue to lead the policy work and share updates.
Looking ahead, GÉANT and NORDUnet will maintain the AARC website and GRNET will continue to operate the AARC CAT platform. A dedicated editorial board led by Sally Chambers (DARIAH) and Hannah Short (CERN) has been established to evolve and maintain the AARC Handbook.
“It has been a privilege and a pleasure to work with such an effective team over the years. Looking forward to more years to come.” – Licia Florio, Senior Strategy and Policy Officer at NORDUnet and AARC TREE Project Coordinator
