Introduction
The research and education sector has over the past decades developed a global identity federation ecosystem which has simplified access to content, services and resources for their community. The eduGAIN interfederation comprises over 80 national federations connecting more than 8,000 Identity and Service Providers. On a national level even more services and institutions are connected. The sector has been able to achive this by creating a highly interoperable ecosystem, where both a high level of technical, as well as policy and trust interoperability has been accomplished, through the joined implementation of various specifications. The joined journey of establishing this ecosystem has enabled the emergance of a global research and education trust and identity comunity with strong bonds and decades of experience in deploying and operating identity federation at scale.
REFEDs, the Research and Education FEDerations group, has been instrumental in providing an open meeting place for articulating the mutual needs of research and education identity federations worldwide. Over the years, REFEDS has addressed issues and topics based on the interests and requirements of its participants. This includes mostly policy, but also some technical and outreach topics in areas such as interfederation, privacy, assurance, relationships with partner communities, marketing, and support of emerging federations.
While REFEDs as such has no bias towards a specific technical implementation, the fact that the SAML 2.0 specification is currently the dominant protocol in identity federation in R&E has had some impact on various specifications created by REFEDs. This ranges for protocol specific sections, to assumption on how a specification would be implemented operationally. The rise of protocols like OpenID Connect, OpenID Federation and the emergence of decentralized, wallet based ecosystems requires a revisit of the specifications. Not only should it be investigated in what way the specifications may be implemented in these protocols, in addition we must assume a multi-protocol ecosystem will emerge and exist for several years to come. This means the specifications may also need to take into account how to go between protocols as it meay be required to translate between not just technical credentials, but also policy and trust frames.
This document provides a first assesment on how the current REFEDs specifications (Nov 2023) may be leveraged in an OpenID Federation (Draft 31) based federation and in a wallet ecosystem based on OpenID Federation and the OpenID4VC specifications. For the latter it should be noted that as this ecosystem and its standards are still being developed, the statments and assumptions on how REFEDs specification may be relevant should be considered speculative.
REFEDs specifications
source: https://refeds.org/specifications (Nov 2023)
Specification types
REFEDs identify 5 types of specifications:
- Entity Category, defined in RFC8409, is a metadata 'label' applied to identity providers or services which signal that they belong to the category which is described in the Entity Category specification. Metadata consumers which understand the Entity Category can alter their behaviour depending on the categories that the entity belongs to. Entity Categories may be used to signal commonly used attribute requirements, or commitment to a certain set of behavioural rules. Taking "Hide from Discovery" as an example: identity providers in this category do not want to be listed by default in discovery services; metadata consumers may be service providers that build their own discovery interfaces, or the metadata consumer may be a third party discovery service.
- Assurance Certification, defined in SAML V2.0 Identity Assurance Profiles Version 1.0, is a metadata label which can be applied to identity providers or services to signal that the entity conforms to the requirements of an identity assurance framework. The Assurance Certification can be self-asserted, or require validation by the registration authority (federation). An entity may conform to more than one Assurance Certification.
- Profiles, which define a standard to signal certain behaviour in a federated authentication transaction, and how to respond to such a request.
- Metadata Extension, provide an extention to existing metadata profiles.
- Frameworks, are currenlty basically assurance frameworks, which provide a structured means of describing or defining the main sources of assurance provided within the federation by the member entities or the federation itself.
OpenID Federation implementation of specification types
OpenID Federation shares many concepts with the existing SAML based federations as currently deployed in R&E. The basic entities (OP, RP and trusted third parties like TA or IA) and the interactions between these can all be represented in OpenID Federation in a similar fashion as these exist in a SAML R&E federation.
- Entity Category: Grouping of entities is typically done via a:
- Trust Anchor or an Intermediate. All entities with similar behavious are members of the same intermediate (or trust anchor)
- Trust Mark could also be used. A trust mark is created by a trust mark owner.
- The trustmark owner must be trusted and listed as such by the federation TA
- A Trust Mark may be self issued.
- Assurance Certification Signalling assurance certifications is done using so called Trust Marks.
- Profiles, signalling certain behaviour as part of a transaction is generally covered in the underlying standards like OpenID Connect and OAuth 2.0. The capablity for signalling is often available, however the semantics may need to be adopted
- Metadata Extension, provide an extention to existing metadata profiles is allowed in the OpenID Federation specification. For broad acceptance and implementation of an extention it may be needed to engage with the OpenID Foundation, e.g. via de RandE working group
- Frameworks, are currenlty basically assurance frameworks, which provide a structured means of describing or defining the main sources of assurance provided within the federation by the member entities or the federation itself.
Wallets
WIP
Overview of findings
| specification name | type | Applies to entity | Asserted by | Attribute profile | Entity behavioural rules | Attribute requirements | In scope for OpenIDFed | In scope for wallets | SAML Specific Protocol requirements |
|---|---|---|---|---|---|---|---|---|---|
| Research and Scholarship (R&S) v1.3 | Entity Category | SP | Registrar |  |
|
| |  |
|
| Research and Scholarship (R&S) v1.3 | Entity Category | IdP | IdP | |
|
| | | ^^^ |
| Hide From Discovery v.1 | Entity Category | IdP | IdP | | |
| |||
| Anonymous Access v.2 | Entity Category | SP | Registrar | |
|
|
| ||
| Anonymous Access v.2 | Entity Category | IdP | IdP | |
|
| ^^^ | ||
| Pseudonymous Access v.2 | Entity Category | SP | Registrar | |
| ||||
| Pseudonymous Access v.2 | Entity Category | IdP | IdP | |
| ^^^ | |||
| Personalized Access v.2 | Entity Category | IdP | Registrar | |
| ||||
| Personalized Access v.2 | Entity Category | SP | Registrar | | ^^^ | ||||
| Code of Conduct v.2 | Entity Category and Best Practice | ||||||||
| Sirtfi v1 & v2 | Entity Attribute | SP | SP |
Legenda for relevance column: Under investigation 
Not relevent Relevant 
Updates to wording and/or implementation required
Detailed discussion
Research and Scholarship (R&S) v1.3
- The Research and Scholarship (R&S) v1.3 specification describes an Entity category which is applied to both IdPs and SPs.
- The SP compliance to the specification is asserted by the Registrar.
- The specification includes an attribute profile which defines the following attributes:
- shared user identifier
- person name
- email address
- affiliation (optional)