This document is a product of the User-Managed Access Work Group. It records the scenarios and use cases governing the development of the User-Managed Access protocol and guiding associated implementations and deployments.
- Hasan Akram
- Eve Maler
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Table of Contents
Introduction and Instructions
This document is a product of the User-Managed Access Work Group. It records the scenarios and use cases governing the development of the User-Managed Access protocol and guiding associated implementations and deployments, and outlines technical issues raised thereby.
Please use the scenario template near the end of this document in adding new scenarios and subordinate use cases. 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.
Scenario: Sharing a Calendar with Vendors (Accepted)
Submitted by: Eve Maler
Online calendars are an example of personal data that is readily shared with other people in a manner that evokes VRM paradigms. Because calendar data is fairly volatile, static calendar snapshots are rarely shared; rather, a calendar feed is provided and authorized recipients can pull fresh calendar data as required. The data is often considered sensitive and is expected to be kept secure, hence "private URLs" and (minimal) ACL features offered by Google Calendar and other hosts.
In this scenario, personal online calendars are shared with "vendors" (online services) rather than other individuals, and they are shared in such a way as to allow permissioning and auditing from a central location rather than wherever the calendar is hosted. For the purposes of this scenario we'll focus on sharing a single online calendar (such as for "work", "soccer", or "travel") as a unitary Web resource, on an ongoing basis, with one or more individually-authorized recipients.
User interface mockups of a calendar-sharing interaction can be found in the initial blog post made about ProtectServe and, in somewhat more sophisticated form, slides from a speech made at an identity conference.
Following are some motivating circumstances in which calendar-sharing with vendors may make sense. (NOTE: All references to real vendors are hypothetical.)
Travel Calendar Sharing with Vendors
Alice, who is based in the Seattle area, has an online calendar that specifically contains business travel details such as flights, hotel stays, and car rentals, and since she travels quite frequently and often to international destinations, she wishes to share it with the following vendors:
- Her Visa credit-card company, Chase
Often when she tries to charge European hotel stays to her Chase Visa, the credit card company denies the charges or asks the hotel desk clerk to put her on the phone to make sure it's really her flitting around Europe and racking up big hotel bills. To let Chase know ahead of time what her travel plans are, Alice decides to share her travel calendar with them on a long-term basis so they can know ahead of time that it's likely truly Alice who's putting a Barcelona hotel stay on the card.
Note that this recipient of her data already has a lot of quite personal and sensitive information about Alice, so she's fairly comfortable giving them access to this data under certain conditions, such as refusing to accept third-party direct marketing.
It must be possible for Alice to cut off the flow of travel calendar data to Chase (even though she continues to use that card for personal purchases) when Alice is told that she has to begin using a corporate AmEx card for all business travel purchases.
- The Seattle Times newspaper delivery service
She'd like to avoid having to go to their website to put her newspaper delivery on hold every time she travels. By sharing a travel calendar with the delivery service that accurately reflects when no one will be at home, she saves one more to-do item as she prepares for each trip.
This is data she would have had to share with the service "manually" anyway (by filling out a web form or using the phone), so she already had to trust the service not to rob her house while she's away. It's likely her full travel calendar contains more data than the service strictly needs, however.
- The U.S. Postal Service
Instead of having to go to the Post Office or its website to fill out a mail hold form, she wants to let them know automatically. This is very similar to the Seattle Times situation, but in our project we need to solve for being able to attach different data-sharing policies and possibly have a different data-sharing lifespan between the two.
- Her mobile carrier, T-Mobile
Alice would like to be offered the option to purchase pre-paid roaming minutes when she travels overseas. By sharing her travel calendar, she can let T-Mobile know that she'll be in Brazil next month and would welcome a special offer on mobile roaming. (Note that this use case has an element of volunteered personal information to it; by positively choosing to share her information, Alice gets new opportunities to transact with vendors.)
- Her travel data social-networking sites, Dopplr and TripIt
Alice wants to keep all her "source" travel information in one place, but some of her friends and colleagues use different Web 2.0 sites to share such information. Rather than re-input all her travel destinations into Dopplr and TripIt, she'd like to let them pick up her planned locations and trip dates from her travel calendar.
Today, Dopplr and other similar sites often use OAuth to share such information, but the actual data passed isn't standardized, and the protocol for creating that long-term connection between the sites is OAuth. (See the forthcoming scenario Granting Service Access to a Photo Set for more observations on this flavor of scenario.)
Soliciting Timely Interactions from Vendors
Alice happens to work from home. Her typical work day is very busy, and she rarely has time to sit on hold when calling the various vendors in her life. She has a calendar that exposes the times during the day when she is free to accept a phone call or consider an invitation to a meeting or other event. She would like to share this information with the following vendors:
- Her TV cable carrier, Comcast
Alice's TV cable system has stopped working, and she needs to have a Comcast repairman come over to the house to fix it. She's too busy to spend time jockeying with the customer support person on the phone about which three-hour period she might be free, so she decides to let Comcast get a limited view into her potential free times so they can send her an event invitation for a repair slot.
- Her general-practitioner doctor's office
Alice needs to talk to the medical assistant in her doctor's office, but it's impossible to get hold of her. The MA calls while Alice is on a telecon but the MA can't leave a substantive message because of HIPAA laws/fears, and then when Alice calls back, of course the MA is in the middle of making a series of other calls and can't be reached. It's a "telephone tag" nightmare. Alice would like to share her free/busy times for the next few days so that the MA can at least pick a likely time to call her successfully.
Use Case: Separate Resource Host, Relationship Manager, and Recipient (Accepted)
Submitted by: Eve Maler
The most generic possible configuration of protocol endpoints solving this scenario is to have one service hosting the calendar in question, a different service getting permissioned read access to it, and yet a different service functioning as the authorization manager, all of them "in the cloud" from the perspective of the user and all operating on the open Internet rather than on a corporate intranet (since our user is an individual acting on her own behalf). This configuration is illustrated below.
Scenario: Controlling Two-Way Sharing of Location Information (Pending)
Submitted by: Eve Maler
- Authorizing user Alice, who chooses to set and share her current location through various applications that she accesses with a commercial off-the-shelf browser
- An application that serves as an Authorization Manager (AM) on Alice's behalf, orchestrating which location applications can write to and read from other applications
- Web-based location applications called HotLocale (H1) and HipHappeningPlaces (H2) that are Hosts of location information on Alice's behalf
- Web-based location applications called RovingAround (R1) and RoadWarrior (R2) that are Requesters of location information on Alice's behalf
Today's location services such as FireEagle, BrightKite, and Dopplr let Alice set her location within any one of several applications, and then use OAuth-enabled connections to propagate that information through other such services. Since Alice can end up "chaining" services this way quite easily, with a thicket of pairwise connections, it's valuable for her to know and control where this information is flowing to. In this scenario, a user of HotLocale and RovingRound wants to arrange to connect them up so that her location can be propagated among them, and she wants to get a global view through her AM about who's allowed to do what, so she can change and stop permissions in a coordinated way.
Note: This scenario is not exploring anything other than person-to-self sharing. How Alice exposes her location to other people and companies should be the subject of a different scenario, as warranted.
Nature of protected resource
API endpoint. For example, see the FireEagle developer documentation. The resource being protected is a single endpoint URL, with different options and parameters possible for using it. The possible scopes in today's location services tend to include (a) whether the requesting app (client) can write the user's location, and (b) to what degree the client can read the user's location. For example, see the FireEagle scope permissions documentation; the location-reading options include: no read access, as precise as possible, postal code level, neighborhood level, town level, regional level, state level, and country level.
Current OAuth-protected usage of location services such as FireEagle and BrightKite assumes a person-to-self sharing model, where Alice has login accounts at the various host and requester apps, and wants to instruct them to share her location among themselves on her own behalf; an UMA-enabled version of this would allow her to control such sharing centrally at her AM.
Nature of policies and claims
For person-to-self sharing, a typical policy might require the requesting party to be able to authenticate as Alice directly at the AM (that is, dictating a particular Step 2 web-server flow that uses normal OAuth user authentication), or might require a claim that it is an authenticated Alice asking for forge the connection. Further, a policy might set (unilateral) boundaries on which scopes can be accessed.
This scenario is 1:1. There is no need to aggregate multiple resources from multiple hosts, for example.
The same requester app might both read and write location data (by using different methods with the same API endpoint), which allows it to write data to a host while still remaining a requester (think "requester of API access"). With today's OAuth-enabled location services, the services act relatively "peer"-ish, in that they have each done the necessary integration to support any one of them serving as an initial host with the others being requesters. So it could be said that the same app might be a host for some users and a requester for others, and/or might be set up as both a host and a requester for the same user's location; however, the latter may be very confusing given current OAuth realities.
Today's OAuth-enabled apps require static introduction and configuration, but the light weight and low security of these Web 2.0 services suggest that dynamic introduction is a possibility as long as the location API is well-known/standardized.
Protected resource discovery
Today's OAuth-enabled apps advertise this location in the process of static introduction and configuration, but with a well-known/standardized location API, it seems possible that a location service host could advertise its endpoint through dynamic means such hostmeta/XRD.
Below is a screenshot showing that FireEagle and Dopplr have the capability today to have two-way location information flow. Our user wants to be able to see this "combinatorily", for all connected location services and indeed for all such services on the web that she chooses to use for hosting any data or content.
Assumptions and Preconditions
This scenario assumes that Alice has an account at each of AM, H1, H2, R1, and R2. These accounts might or might not be driven off of federated login, for example, Alice might log in to HotLocale through Google and RoadWarrior through Facebook.
This scenario assumes that AM, H1, H2, R1, and R2 are all UMA-enabled but have otherwise not met before. (Simplified circumstances that assume prior introduction are described in their turn below.)
This scenario assumes that H1 and H2 use a hypothetical standard location API that R1 and R2 are configured to understand, and that H1 and H2 expose APIs through URLs that differ per user in some fashion (e.g., through a URL query parameter or through a part of the URL path).
Use Case 1: Alice Sets Up AM Protection Over Location Information at HotLocale
This flow can be embedded in other flows, or can be standalone.
- H1 asks Alice to choose an AM to protect her location information in H1
- Alice tells H1 her preferred AM
- H1 discovers how to get started connecting to the AM
- Alice is redirected to AM to log in as Alice-on-AM, consent to protection, and choose a policy that applies to H1's endpoint for her
- The policy indicates that the requesting party must accept her chosen scope of access, which is "write, read-city"
- The policy indicates that the requesting party must be able to log in at the AM synchronously as Alice-on-AM and consent
- The policy does not otherwise discriminate against particular Requester apps (note that we don't currently have a way to do this; do we need to?)
- She labels the policy "location services policy" (outside the scope of the UMA protocol)
- Alice is redirected back to H1 to continue what she was doing before
The identical sequence can be done with HipHappeningPlaces (H2).
Use Case 2: Alice Shares HotLocale Location Access with RovingAround and RoadWarrior
- Alice visits H1 and logs in as Alice-on-H1
- Alice decides to share access to her location information in H1 with R1 (if use case #1 has not been done, it must be done at this time)
- Alice asks H1 to give her a "share" URL to use
- Alice visits R1 and logs in as Alice-on-R1
- Alice gives R1 the "share" URL from H1 and asks it to set up access to her location information there
- R1 attempts to access the URL and discovers H1 uses a location API that R1 understands
- H1 redirects R1 to the AM as unauthorized
- AM tells R1 it needs to provide a claim acknowledging the offered scope (need to standardize this claim request/response)
- R1 sends the claim to AM
- AM tells R1 it needs to redirect its user (Alice) to AM to authenticate (add this as a special indicator/claim request to the protocol?)
- R1 redirects Alice to AM to authenticate and consent
- AM concludes that Alice authenticated correctly as Alice-on-AM
- AM issues an access token to R1 for location information access of the offered/accepted scope and redirects Alice back
The identical sequence can be done with RoadWarrior (R2), except that once HotLocale is introduced to the AM, it never needs to be introduced again, so the optional embedded UC1 block isn't ever done again unless Alice wants to switch AMs.
Use Case 3: Alice Monitors and Controls Location Information Access from Her AM
To monitor access, Alice interacts with value-added functionality provided at the "data-sharing relationship manager" application that serves as her AM endpoint; that is, this use case does not involve standardized UMA protocol behavior. These interactions might include:
- Looking at a unified log for occasions when both RovingAround and RoadWarrior accessed HotLocale on her behalf, and what they did on those occasions
- Looking at a unified log for occasions when RovingAround accessed both HotLocale and Alice's calendar application (not part of this scenario) on her behalf
- Looking at a unified log for all hosts to whose resources she applied her "location services policy", including both HotLocale and HipHappeningPlaces
- Showing a graphical depiction of location host and requester access relationships and their types, if it is able to characterize hosts according to the APIs/resource types they expose
To control access, Alice may take various actions:
- If Alice discovers that her HotLocale account was hacked, she can go into her AM and revoke access to it from all requesters. If access tokens issued to requesters are sufficiently short-lived, the next time any of them seeks access by presenting a refresh token in order to get a new access token, they would be denied access. (would the OAuth 2.0 token revocation extension help here?)
- Alice may decide that she wants to limit access to include reading her location from HotLocale only, instead of reading and writing her location, because the previous situation was too confusing. She can change the "location services policy" to limit the scope list. If access tokens issued to requesters are sufficiently short-lived, the next time any of them seeks access by presenting a refresh token in order to get a new access token, they would be asked for a claim acknowledging the reduced scope and be issued a new access token.
- Scope claim: Need special claim request/response regarding some scope list being offered by the authorizing user, as imagined above?
- RESTful API: Do we really need the assumption that the protected resource URL has something special and authorizing-user-specific about it (with the invention of the "share URL" concept above)? Note that the share URL doesn't have to be a secret URL; it should be protected by UMA regardless (we'd need to think about how the host registers resources if we do make the "share URL" assumption). Is there some way we can handle current common API practice, where the endpoint URL is static and doesn't change per user?
- Host API dynamicism: Use case 2 could be called "host-initiated access"; this only works if the host uses a standard API that the requester can discover and work with. Do we need to build an alternative use case that assumes a proprietary API (akin to current OAuth usage), non-dynamic introduction of the parties, and requester-initiated access? How does scope work in that case – does the AM just end up recording the requester-offered scope?
- Redirection of requesting user: Do we need to bake a special claim request/response into UMA for handling the person-to-self flow (or at least usage of the web server user-authentication flow) in Step 2 so that the requester knows for sure to redirect the user to the AM? A requesting user who isn't Alice may not need to "authenticate" there, but they could (e.g.) provide a special code that was given to them by the authorizing user offline.
Scenario: Packaging Resources for E-Commerce Vendors (Accepted)
Submitted by: Eve Maler
This scenario focuses on the typical set of information that we hand over to online vendors repeatedly, and the desire to avoid sharing the data "by value", instead focusing on how to share it "by reference" (pointers).
Let's look at how an online buying scenario might look today.
- Bricks and mortar
Maya recently became extra-concerned about identity theft and fraud because a friend had his bank account stolen from, and she has decided to buy a shredder so she can dispose of old bills, credit-card offer junk mail, and outdated backup CDROMs. She visits her local Staplers store, prepared to buy a shredder that day (with cash! hey, it's anonymous), but can't find a shredder in stock that handles CD shredding.
- Comparison shopping
She goes to Google and a couple of specialized comparison-shopping sites and plugs in search terms like paper shredder cdrom, but can't easily figure out which ones have the features she wants, but the prices at Staplers.com, the site for the local store she was just in, look good and she decides to just go ahead and shop there.
- Clicks and mortar
Once Maya is at Staplers.com, she finds a suitable shredder and adds it to her shopping cart (which is, so far, "anonymous" with respect to everything but some sort of device identification, possibly based on a cookie, associated with her browser session).
Following are some key questions we can ask, identified by whether they capture an identity management (IdM) issue, a vendor relationship management (VRM) issue, or a social networking issue. (Note that some of these questions highlight scenarios and use cases that the calendar scenario has already captured. Some of these might want to get turned into unique use cases for this scenario.)
- Can we imagine better ways for Maya to set up a data-sharing relationship with Staplers.com? (IdM, VRM)
- She's planning to move in a couple of months, and that means the address information Staplers has saved will go stale.
- Same for her credit card: it will expire next year. When these items change, she has to go fix them at dozens of sites.
- She's not crazy about having to supply things like credit card information to every vendor on the web.
- Is it possible for Maya to have a "one-night stand" with Staplers.com rather than a long-running relationship? (IdM, VRM)
- ...if she doesn't really want Staplers to track her purchases, browsing habits, or anything else over time.
- ...if she wants to share only the minimum personal information Staplers really needs to do its job this once, and then only temporarily.
- Can we imagine betters ways for Maya to engage in the shopping-around process, possibly involving her sharing more data about herself? (VRM – particularly volunteered personal information!)
- What if she could "issue a personal RFP" indicating the price and features she's interested in, and entertain vendor site "bids", such that not only Staplers.com and OfficeArmory.com could bid, but also Ann, who has a used shredder she'd like to sell?
- What if she could let Staplers know her customer-support phone line preferences, such as wait time and ad-playing tolerance?
- What would it look like for Maya to get a unified understanding of all of her data-sharing relationships? (VRM)
- She sure would like to get a handle on her own "personal data analytics" – "who knows what" about her.
- If Staplers behaves badly (gives out her data against her rules or allows a data breach to occur), she wants to have better options for recourse.
- ...and she wants to be able to cut off their future access to information about her.
Maya shares the information about herself that Staplers.com needs at the beginning of her e-commerce relationship with them, but instead of having to share it "by value", she shares it as some form of pointer to a package of resource pointers that Staplers can dereference and refresh as they needs to over time. She can change the underlying information whenever she wants to without worrying about paying special attention to Staplers (or any of the other hundred e-commerce sites with which she has registered.
- Maya (User)
- Authorization manager (AM)
- Personal datastore (Host) in which authoritative versions of resources to be shared reside (that colocation of AM and Host is not a requirement, but for this scenario the individual resources are assumed to live on a single Host)
- Staplers.com (Requester)
- User can package and reuse pointers to resources commonly needed for e-commerce into a rolled-up resource that is available for access by multiple requesters (assume for this scenario that all the individual resources and the rolled-up resource are available from the same host in the "personal datastore" model).
- The data involved is "self-asserted" to a first approximation. (The credit card data we often share today is "asserted" solely by us, but then the vendor validates it out of band.)
- Requester can handle receiving and dereferencing both a pointer to a package resource and pointers to individual resources.
- AM can manage the offering and meeting of terms for resource-sharing for the whole package and can take advantage of efficiencies where the terms for individual resources are identical (possibly similar to the Distributed Services scenario).
- Requester will often represent a requesting party who is the same human being as the authorizing user, and can take advantage of efficiencies in any real-time requester/AM/user connection for obtaining user consent in that moment.
- Requester, host, and AM are likely to be willing to deal with each other solely on the basis of the user's say-so (unlike in the personal loan scenario).
Use Case: Online Purchase with Setup of a Long-Running Account Relationship (Accepted)
Submitted by: Eve Maler
Preconditions: Maya has already stored, and packaged together, pointers to the set of relevant resources frequently needed for online purchases:
- Her desired credit card number, expiration month and year, security code, name on card, and billing address
- Her shipping address and phone number
- She goes to Staplers.com and puts her desired shredder in her shopping cart.
- When she goes to check out, she's presented with a requirement to register for an account. The form has fields for the data listed above, but also has a new field for "Personal data feed".
- In a separate browser window, Maya visits her Relationship Manager and generates a unique URL representing the disclosure package she wants to offer Staplers (CC number etc.) and the policies she expects it to adhere to in accepting her information (they can't sell her data etc.).
- She goes back to Staplers and pastes the URL she just generated, and presses a button that says "Share personal data".
- The Staplers web application follows the link, discovers it has to agree to a set of policies before getting through to the info it needs, decides to agree, and gets through.
- Staplers retrieves data items with content-types that indicate they contain CC numbers, addresses, etc., and then displays the values retrieved in the regular registration form fields, possibly with some graphical indication that Maya can override any one of them.
- (later) Maya can use her RM to view the activity related to Staplers' retrieval of her information, check what she's told them (and others), and also check the conditions under which she released information.
- How can we ensure that the sensitive data is secured in motion (while being conveyed to Staplers)? (generic across all scenarios)
- What is the right UX paradigm for letting Maya override information? Ideally, any info that's changed should be updated in the RM, not on the Staplers site. But if she wants to override a value just once, with values to be updated in future pulls of the feed, the right place to change it is on the Staplers site itself. Does this latter situation sound likely?
- What about interfaces where the credit card information is provided at a separate point in the process? How should that be accounted for? Perhaps, except for subscription-type payments (ongoing over time), this information is not part of the registration bundle and is provided (by reference or by value) only at purchase time.
Use Case: Engaging in a Purchase "One-Night Stand" (Accepted)
Submitted by: Eve Maler
This is the same as the first use case outlined above, except that Maya provides her resource package not as part of a request to register a new account, but as part of a one-time purchase. (Some websites today allow for purchases without registering, and are prepared not to give you a browser cookie or retain your information beyond necessary for the purchase and its aftermath.)
The policies Maya chooses in this case are likelier to be more stringent about not retaining personally identifiable information (PII) for any significant length of time, and may ask the vendor to generate "positive" assurance messages about policy adherence (not just silent adherence).
(The protected-inbox scenario might play an especially important role if Maya is engaging in a one-night stand purchase, since it enables the vendor to report product recalls and such to Maya without her having to expose other more compromisable communications endpoints such as persistent email addresses or phone numbers.)
Scenario: Distributed Social Networks (Pending)
Submitted by: Christian Scholz
If you look at the social networking scene today one thing is obvious already: There is lot of data online on various services and much of this data is redundant because it is available in various copies which are usually not synced. The main area for this problem is probably profile and friendship/contact information. On each social network or service you register you usually have to enter your profile information again and try to find your contacts.
With the advent of more and more of such social services the amount of redundant data will grow even more and this will lead to a acceptance problem.
The Service Catalogue idea
It is unlikely that users will centralize all their data in one place. It's more likely that data will be distributed even more. So one problem might already be to manage all the places where data is stored about you or where services can provide functionality on your behalf. One solution to this might be a concept called "Service Catalogue" which came up in discussions in the open web/DiSo/DataPortability communities. The basic idea is to have a list of all these places stored under your control which can be queried by services.
Another point is that for reducing the amount of copies of your data it is necessary to link to your data instead of copying it (or even worse asking the user to type it in again). The Service Catalogue can serve basically as such a link list where each service/type of data is marked up with a location (URI) and type (probably another URI). Obvious things to link to are your profile and contact list but other things make also sense, like photos, videos, blog posts, recommendations, your attention profile, travel information and much more.
Now if you want to use a new service you do not even need to "register" but you simply authenticate with it (e.g. with your OpenID) and point it to the location of your Service Catalogue.
The problem is of course how you authorize that new service to get access to all the other 3rd party services. OAuth is one possible solution but at least if the default mechanism for retrieving a token is used this means that the user has to be redirected to each of these 3rd party services in order to give consent for the new service to use that data. Moreover OAuth does not contain a mechanism to define what permissions are given exactly. One can imagine that for some services you want to give out your full profile and for others maybe just your name. Moreover this might not only apply to the service level but also to the user level. E.g. you might want to give a contact tagged "superfriend" your full profile while for somebody tagged "no idea how he landed on my contact list" you only want to give out basic data.
For the sake of usability what we need is a single page where you can define the relationships between that new service and all the other services in your Service Catalogue. Moreover it would be helpful to have certain profiles stored to quickly assign one to this new service.
Possible use cases
Here is a list of use cases which come to mind:
- User logs in to a new service and authorizes 3rd party services
- User adds a new 3rd party service to the Service Catalogue
- User changes the permissions for a service
- User manages permission profiles
Scenario: unique-title (Pending)
Submitted by: participant-name
(Provide description of the scenario with all nontechnical particulars, noting requirements, constraints, and other observations. Avoid diagrams.)
Use Case: unique-title (Pending)
Submitted by: participant-name
(Provide description of a use case matching this scenario with all technical particulars, such as the topological configuration of protocol endpoint entities, potential wireframes, listings and assessments of technical issues, and anything else helpful.)
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.
Issue: Authorization Manager Endpoint Discovery
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.)
Issue: Handling the Resource URL and Provisioning It to the Consumer Site
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.
Issue: Processes By Which Consumers Meet the User's Data-Sharing Terms
Some of the vendors mentioned in the calendar scenario are big companies; can standard (and machine-readable) data-sharing contract terms be developed and pre-negotiated such that, when such contracts are offered by an individual, they are likely to be accepted and met? Small companies such as a modest medical practice may need a human-accessible interface and the option of an "I Agree" button so that the person manually fielding Alice's offer of data can complete the transaction.
It may be necessary for us to consider "partial measures" in the V1 UMA effort to improve adoption. Some such measures are: terms that can be passively accepted ("I Agree") rather than terms that require positive demonstration of intent (such as payment receipts); policies that don't require explicit agreement on the part of the recipient but are somehow attached to the data supplied ("sticky policies"); and policies about which the recipient is merely informed rather than asked to agree with.