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This document is currently under active development. Its latest version can always be found here. See the Change History at the end of this document for its revision number.
Editors
- Hasan Ibne Akram (lead editor)
- Gerald Beuchelt
- Domenico Catalano
- Maciej Machulak
- Eve Maler
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- Christian Scholz
- Thomas Hardjono
Intellectual Property Notice
The User-Managed Access Work Group operates under Option Liberty and the publication of this document is governed by the policies outlined in this option.
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Table of Contents
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Please copy and revise an existing scenario in adding new scenarios and subordinate use cases. Each scenario is created as a separate child wiki page with a name like xyz_scenario and then linked from here. Change the status keyword in each scenario and use case title as appropriate, linking to the meeting minutes page explaining the status change:
- Pending: Initial status when first submitted
- Accepted: Needs to be accounted for in UMA V1 and/or its associated compliant implementations
- Deferred: Relevant to the problem space; may be considered in future versions
- Rejected: Out of scope
Edit the descriptions of technical issues and scope questions to reflect (or point to) group decisions about how to handle them.
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Following are discussions of technical issues raised by one or more scenarios and use cases. Acceptance of a scenario or use case will imply agreeing to develop a satisfactory solution to applicable issues.
Issue: Policies Specific to the Web Resource Type
There is a potential need to restrict, anonymize, blur, or otherwise transform a shared resource, possibly based on the unique characteristics of its content type.
With respect to calendar resources, the premier calendar format standard already accounts for a blurring of data details by providing a "free/busy" option in addition to a full-data option. It feels like it should be out of scope to solve for filtering the calendar data cleverly (beyond the format's natural capabilities) to hide Alice's destination, hotel, etc. (though generic solutions such as making events taggable, and then filtering on the tags in a relationship manager interface, come to mind). An "identity oracle" approach (filtering the data into a completely different type) might be necessary if what Alice is trying to convey is simply "don't deliver my newspaper on these days" vs. "here's all of my travel information".
In the Controlling Two-Way Sharing of Location Information scenario, note that FireEagle allows a user to choose to share locations only at the city level, and this level happens to be chosen for the connection that authorizes Dopplr to read the FireEagle location (a different level can be chosen for each application that reads location from FireEagle). As it happens, Dopplr does not offer the same policy capability. Without having to teach UMA generically about all the possible policy options specific to all the kinds of information in the world, is it possible for each Host to teach each AM about the policy options it offers, in some way that lets the the relationship manager application surrounding the AM present user interface options to see and select these policies? Seeing may have less protocol impact than selecting, and seems to be a minimum value-add if the goal is to allow OAuth users to get a global view.
Some data-usage policies and terms may possibly have an interaction with some resource types, such as requiring recipients to discard volatile data after a period dictated by the data's type.
It has been observed that if fine-grained calendar filtering were a solved problem, different calendar sites could be shared with different friends as a way of managing minimal disclosure through indirection.
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The mockups linked in the calendar scenario imagine that the user's authorization manager endpoint (what we imagine Alice will perceive as the name of her relationship management service) will be handled as if it were an OpenID, with introductions to popular relationship manager services offered in an array by potential UMA Hosts much in the way that the RPX solution presents options. (The user always has the ability to self-host an authorization manager endpoint, similarly to self-hosting an OpenID provider – and they might even be colocated.)
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The mockups linked in the calendar scenario imagine the simplest possible situation: The Consumer site literally asks for exactly the kind of information it needs, and the user copies and pastes a URL into a field.
This is how calendar feeds, photo streams, RSS feeds, and other such resources are shared today; it works but we need to consider its scalability to arbitrary types of information. There are several challenges here: The Consumer's ability to handle the information, its way of expressing the desire/need for the correct information, and the user's (or user agent's) ability to provide it in a convenient and correct fashion.
In addition, the relationship manager interface is shown having some knowledge of that resource as a unique object. We need to consider how to let the AM and SP communicate about this information appropriately.
In the case of the photo set scenario, note that in OAuth usage today, the resource-based interaction is often accomplished silently from the user's perspective: the desired combinatorial effect simply "happens" as if the feature that was "outsourced" to a third-party app were native. Perhaps this is possible in the UMA approach.
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An AM has two major tools at its disposal in allowing access to a user's resources: policies declared by the authorizing user, and terms which the Requester must meet in order to gain access. To a first approximation, policies can be unilaterally applied, whereas terms require two parties to come to agreement.
Because policies are anticipated to be applied by an AM "silently" (out of band) with respect to the UMA protocol, this is an opportunity for AM business value and we should not dictate any answers here. But following are some policies that could be useful:
- How long to allow access: once, some number of times, for some period, indefinitely until the user says to stop, etc.
- Whether to let the user exercise a "right of refusal" by some interactive means (such as SMS) when a Requester approaches a particular resource: every time for that Requester, only the first time for that Requester, every time for every Requester, etc.
By contrast, terms might take some of the following forms:
- Make the Requester promise not to sell or otherwise commercially use the data thus acquired (in Creative Commons-like fashion)
- Require the Requester to pay the user ten dollars
The following hypothetical wireframe (with hypothetical Creative Commons-like sets of standard terms) imagines what a user interface could look like for an AM's default policy and term settings for all resources it manages:
The UMA group is hoping to borrow from the work of others in using any standard sets of terms that might exist, for example as might be developed by the Kantara Information Sharing (UD-VPI) WG. However, even if this area is well fleshed out, major design questions remain.
Human interaction by a party "behind" the Requester
Some parties behind a Requester's actions may be big companies like credit card issuers, large e-commerce sites, or government agencies – but some may be small organizations, such as a dentist's office. Small organizations may need a human-accessible interface and the option of an "I Agree" button so that the person manually fielding an offer of data can complete the transaction.
Requester resistance to user-driven terms
It may be necessary for us to consider "partial measures" in the V1 UMA effort to improve adoption. For example, it may be more difficult to demand evidence of positive action (such as payment) from a Requester vs. demanding a simple statement of passive acceptance of terms (such as "I agree not to sell the data"). This would be a natural first step if Requesters are at all amenable to the notion of user-driven terms.
If we discover that Requesters are resistent, we may need to consider options for allowing the user to passively inform the Requester of policies such as "I ask you not to sell this data", rather than requiring action on the part of the Requester to accept such terms. Or given that Requesters are today in the habit of making their own terms of service and privacy policies known to users in passive fashion, we may need to account for a case where the user's terms amount to an opening gambit of "What can you offer me?" in a contract negotiation.
Depth of contract negotiation
There is some minimum functionality needed around a sequence roughly like the following:
- AM presents terms based on user configuration of same, followed by...
- ...Requester demonstrates that it meets the terms presented
However, there are many layers of sophistication we could get into, depending on where our scenarios take us. For example, is it important for the user to be able to specify "you must satisfy these terms 'or better'"? If so, what does "better" mean? Do we have to solve for "I will sell you n pieces of data for terms X, but n+m pieces for terms Y"?
Legal enforceability and terms persistence
We have discussed whether machine readability of terms is strictly needed, since having a URL that persistently refers to a human/lawyer-readable version seems to suffice in a lot of cases today for string-matched satisfaction (no complex negotiation), including very complex enterprise cases. Nat Sakimura's blog post on contract exchange suggests various ways to characterize, share, negotiate, and record data-sharing contracts. How we answer these questions also has an impact on our goals around simplicity, particularly our emerging goal around not adding undue cryptography burdens.
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Common Building Blocks (Dimensions)
As a further refinement to help us in classifying and prioritizing the use cases, we would like to add a section to each use case describing the building-block features or dimensions that are present in a given use case. The current list of features or dimensions are as follows:
Dimension | Description | Example |
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Nature of protected resource | A description of the sorts of protected resources at hosts in this scenario, and the scope values that might be applicable, ideally with real-life supporting evidence. Protected resources appear to fall on a continuum from API endpoint (such as status updates) to content-oriented (such as photos), and further, typical actions on them may usefully be classified in terms of how RESTful they are. | In the location services scenario, protection of a location service (a set of one or more API endpoints) might involve scope values such as "write location data", "read precise location data", and "read location data at a city level". |
Sharing models | A description of what sorts of access or sharing the scenario facilitates. Person-to-self sharing occurs when an authorizing user shares access with a service that is acting directly on the same user's behalf (a la "three-legged" OAuth). Person-to-service sharing occurs when an authorizing user shares access with a legal person operating a service that is acting on its own behalf (a la "two-legged" OAuth, where the client is autonomous). Person-to-person sharing (also known as "Alice-to-Bob sharing") occurs when an authorizing user shares access with a different natural person. (@@Fourth category of "person-to-rep sharing" where the autonomous company's service is operated by a human company rep?) | The location services scenario is an example of person-to-self sharing. The calendar scenario is written to explore person-to-self and person-to-service (@@and person-to-rep?) sharing options, but could also apply to person-to-person sharing. |
Nature of policies and claims | A description of the types of policies, and any resulting claims requested, that might be suitable for this scenario and its use cases. | The terms negotiation scenarios discuss likely claims needed in the course of assessing a requesting party's right to get access. |
Cardinality | An accounting of whether the scenario or any of its use cases necessarily involve multiple instances of any of the UMA entities. | The financial loan scenario by its nature involves a requester having to access multiple protected resources, likely from different hosts. The scenario related to moving resources by its nature involves two different AMs: the user's previously chosen AM and their newly chosen one. This information is often usefully conveyed with an architectural diagram along with descriptive text. |
Colocation | A description of likely cases where real-world applications might want or need to support multiple UMA endpoints. | The health data scenario tends to involve actors that serve as both hosts and requesters. The trusted claims scenario proposes that an application offering AM services might also need to be a requester in order to access the UMA-protected claims of some other ("primary") requester. |
Host-AM relationship | An accounting of how hosts and AM come to meet and trust each other in this scenario or its use cases. Dynamic discovery might be required or forbidden. AMs and hosts respectively might need to be well-known, or at least dynamically qualified before the connection is made. | The health data scenario might have a short list of approved AMs to which many hosts around the world may need to dynamically connect as soon as a new patient needs medical care. |
Protected resource discovery | A description of the anticipated method(s) by which a requester learns about a resource of interest to them. The methods may have a dynamic element to them or may require reconfiguration. The methods may or may not involve direct human assistance. | The calendar scenario could mention that most calendar feeds are shared today through URL copying and pasting. |
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