This document summarizes the various use cases of DI4R. The use cases are categorized by role: whether an entity is a consumer or a producer of attributes.

Functional model

Trust model

also compare trust model to federation/eduGAIN

Technical model

How does verification actually work in IRMA?

https://irma.app/docs/overview/

Verifier: consume credentials from holder

Any entity that normally relies on an authentication flow that also aggregates attributes may use IRMA or other service for login. In this process, the user is challenged with a QR Code to brandish attributes with the help of the wallet app. The wallet app reads the QR code and engages in user interaction: it shows what is requested by the service and which "cards" - previously stored attributes accommodate the request, if any. Alternatively, in this flow the user may acquire new cards to fulfill the request. The wallet then sends the attributes to the service, which can verify them with an background call.

With this method the Verifier no longer trusts an IdP (something that is exposed on the public internet) but trusts the authentication and the possession to the wallet. Arguably, this provides the opportunity to a stronger level of assurance (i.e. two factors to the wallet+possession of the device).

Issuer: SAML attributes into IRMA tokens

An obvious source of "cards" is a SAML federation. In order for a SAML attribute of a user to be converted to a card, the user needs to visit an entity that acts as a proxy. This proxy needs to behave as a SAML SP towards the user and the SAML federation. The user needs to visit the site with the intent of adding a card to their IRMA app so that the IRMA infrastructure can store the data as a card. The user will be logged in to this SAML SP which will consume the attributes from an IdP / AA then store it to the IRMA infrastructure.

Issuer: 'native' triple stack IdP issuing SAML, OIDC and IRMA

An authentication source may already have to support multiple protocols, (for instance, SAML and OIDC) in order to cater for the modern web environment. A logical extension of this idea is to support an additional protocol, the card Issuer.

Issuer: attribute aggregation from Research AAI/MMS

In a traditional SAML flow the following happens. The goal is to enable user Aladár (A) to manage the authorisation of user Béla (B) authorization to service S, but in a way that this information is not maintained in S but in an external source, the Membership Management Service (MMS). 

1. A logs in on the web interface of the MMS, a SAML SP and an account is created.
2. A creates a Virtual Organization / Community / Group - terminology depends on the actual tool but let's call it (VO)
3. A wants to invite B to his VO. In order to do this, he needs an email address to B. This email address serves as a trust anchor for the moment, therefore it needs to really belong to B and not be compromised.
4. A sends an email invitation to B with a link containing a token. The email is sent by the MMS system.
5. B follows the link to the web interface of the MMS, prompted for login. B may already have a login (for previous participation in other VOs) or needs to create a new one. B may log in with a federate account but it could be the case that there is none, and a local account is created or a VHO account is used. This scenario is made possible by the fact that really the access to the email inbox is what provides the trust for the VO membership.
6. After creating/accessing a local account, the token sent in the link is processed and B's account is now associated with the VO. 
7. B will eventually access a service that needs this membership information, commonly called entitlement.
   1. The service will perform a login flow
   2. with B's user identifier queries the MMS back-end, for instance a SAML AA or an integration. This requires the usage of the same user identifier that was used at the MMS, typically a common OIDC/SAML source.
8. A may revoke the entitlement at any time, which will take effect at the next session: the service accessed will query the MMS and will not get the entitlement.

With the introduction of DI4R, the flow may be significantly simplified. 

1. A creates a VO at the MMS service
2. A sends an invitation to B to the VO
   1. an email is sent to B from the MMS
   2. a card is registered to the registry?
3. B visits the link and receives the card, which is added to the wallet.
4. B visits a service that needs the entitlement and presents the card.
5. (the card is verified in the common registry, therefore revocation is possible

With this solution B does not have to use the same login (i.e. the MMS and the target S do not need to be in the same federation). Possibly, B can receive the card at a page maintained by the DI4R provider. 

Or, perhaps the DI4R provider's web interface serves as a landing page for the invitation?

Overview Use Cases

Sourcing

Revocation

https://irma.app/docs/revocation/

Issuer action

User action