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FIXME: Image + Description
Identity Assurance AA Architecture (
(IAS = Identity Assurance Service)
The Identity Assurance AA model consists of a
- SAML Attribute Authority (AA)
- an additional SAML SP (SAS IAS SP, not a proxy),
- web service or IdP (SAS IAS IdP)
- database
... that could be operated by a trusted third party (e.g. federation) or a research project or community. A research SP only has to make a few configuration changes.
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- User accesses SP with his/her web browser and clicks on login
- User's web browser is sent to discovery service where users chooses his/her IdP
- User's web browser is sent to login page of his IdP where (s)he authenticates (1. factor)
- After successful authentication, the user's web browser is redirected with a SAML assertion back to the SP
- The SP validates the assertion and extracts the user's attributes (at least a unique identifier that is needed for the Attribute Query).
- If all requested attributes have been released and the AuthnContextClassRef (or the eduPersonAssurance attribute) contains the value 'https://refeds.org/profile/mfa' we're done and the following steps are skipped.
Otherwise: - Using the identifier attribute, the SP then performs a SAML attribute query to the Attribute Authority (AA) of the Identity Assurance Service (SASIAS)
- If available, the AA returns the LoA attribute (login at SAS IAS IdP) for this user to the SP
- Using the Shibboleth Attribute Checker, the SP checks the LoA-related attribute (that was queried from the AA). If that LoA attribute is not present or if it does not have the required value, the user is sent to a web page X of the SASIAS.
- Web page X is protected by an SP (SAS IAS SP) itself, therefore the user has to authenticate again, this time using the SAS IAS IdP - as a substitute for a second factor of the Home IdP.
- If authentication at SAS IAS IdP succeeded, a temporary LoA entry is created in database of AA and the user is sent back to SP
- SP initiates login of user again, so (s)he is sent back to his/her IdP (where SSO session is still active) and from there back to the SP, which again initiates a SAML attribute query.
- If the attribute query happened in a reasonably short time interval since the user authenticated at SAS IAS IdP, the AA has released a LoA attribute for the user. Therefore, the AttributeChecker's requirements are met and the user is granted access.
In the above flow it is assumed that the registration of the user with the user directory of the SAS IAS IdP and any identity vetting mechanics have taken place prior to this login flow. The related processes may be subject to local / project / community requirements and are not in the scope of this POC implementation.
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