New UMA solutions for scoped access and centralized AUTHZ

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Session Topic: New UMA Solutions for Scoped Access and Centralized AUTHZ (T4B)

Convener: Eve Maler, Maciej Machulak

Notes-taker(s): Eve Maler

Tags for the session - technology discussed/ideas considered:

Discussion notes, key understandings, outstanding questions, observations, and, if appropriate to this discussion: action items, next steps:


. We shared and discussed the User-Managed Access (UMA) draft solution for loosely coupling an OAuth authorization server and resource server to solve for externalized authorization and interoperable scoped access.



UMA is:



  • A web protocol that lets you control authorization of data sharing and service access made on your behalf
  • A Work Group of the Kantara Initiative that is free for anyone to join and contribute to

  • A set of draft specifications that is free for anyone to implement

  • Undergoing multiple implementation efforts
  • Being contributed to the IETF, in pieces (over the next few months)
  • Striving to be simple, OAuth-based, identifier-agnostic, RESTful, modular, generative, and developed rapidly



 UMA has three phases:



1. Protect a resource (NEW protection model)



  • Alice introduces her Calendar host to CopMonkey:“When CopMonkey says whether to let someone in, do what he says” – and then tells CopMonkey her calendar access policies



2. Get authorization (NEW authorization model)



  • Chase VISA tries to subscribe to Alice’s travel calendar for fraud protection purposes; its client has to get authorization first, for which it may have to present claims to meet Alice’s policy



3. Access a resource



  • Chase now has an access token with the necessary scope to use at the Calendar host: “This means Alice thinks it’s okay”



The presented slides can be found at:

 http://www.xmlgrrl.com/publications/IIW12-UMA-ScopedAccess-May2011.pdf



More information about UMA can be found at:

 http://kantarainitiative.org/confluence/display/uma/Home



Questions that came up about UMA (the group is working on publishing a FAQ with the answers given during the session) were:



  • How can the host be made responsible for incorrect or malicious behavior? In other words, how does host/AM trust work?


  • Have there been any usability studies?


  • Why externalize authorization?