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+<!DOCTYPE html>
+<html>
+ <head>
+ <title>LDP Access Control</title>
+ <meta charset='utf-8'>
+ <script src='http://www.w3.org/Tools/respec/respec-w3c-common'
+ async class='remove'></script>
+ <script class='remove'>
+ var respecConfig = {
+ // specification status (e.g. WD, LCWD, WG-NOTE, etc.). If in doubt use ED.
+ specStatus: "WG-NOTE",
+
+ // the specification's short name, as in http://www.w3.org/TR/short-name/
+ shortName: "LDP-AC",
+
+ // if your specification has a subtitle that goes below the main
+ // formal title, define it here
+ subtitle : "Usecases and Requirements for Access Control for the Linked Data Platform",
+
+ // if you wish the publication date to be other than the last modification, set this
+ // publishDate: "2009-08-06",
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+ // if the specification's copyright date is a range of years, specify
+ // the start date here:
+ // copyrightStart: "2005"
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+ // if there is a previously published draft, uncomment this and set its YYYY-MM-DD date
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+ // previousPublishDate: "1977-03-15",
+ // previousMaturity: "WD",
+
+ // if there a publicly available Editor's Draft, this is the link
+ // edDraftURI: "http://berjon.com/",
+
+ // if this is a LCWD, uncomment and set the end of its review period
+ // lcEnd: "2009-08-05",
+
+ // editors, add as many as you like
+ // only "name" is required
+ editors: [
+ {
+ name: "Ashok Malhotra"
+ , mailto: "ashok.malhotra@oracle.com"
+ , company: "Oracle America, Inc."
+ , companyURL: "http://www.oracle.com/"
+ },
+ ],
+
+ // name of the WG
+ wg: "Linked Data Platform WG",
+
+ // URI of the public WG page
+ wgURI: "https://www.w3.org/2012/ldp/wiki/Main_Page",
+
+ // name (without the @w3c.org) of the public mailing to which comments are due
+ wgPublicList: "public-ldp-comments@w3.org",
+
+ // URI of the patent status for this WG, for Rec-track documents
+ // !!!! IMPORTANT !!!!
+ // This is important for Rec-track documents, do not copy a patent URI from a random
+ // document unless you know what you're doing. If in doubt ask your friendly neighbourhood
+ // Team Contact.
+ wgPatentURI: "",
+ // !!!! IMPORTANT !!!! MAKE THE ABOVE BLINK IN YOUR HEAD
+ };
+ </script>
+ </head>
+ <body>
+ <section id='abstract'>
+ <p>
+ This note discusses usecases and requirements for Access Control for the
+ <a href="https://www.w3.org/2012/ldp/wiki/Main_Page">Linked Data Platform WG.</a>
+ It also outlines a charter for developing a standard for HTTP-based access control.
+ The work delineated in the charter may be pursued in the Linked Data Platform WG or an independent, related WG.
+ </p>
+ </section>
+
+ <section id='sotd'>
+ <p>
+ While the <a href="https://www.w3.org/2012/ldp/wiki/Main_Page">Linked Data Platform WG.</a> did not
+ address Access Control directly, a number of usescases and requirements were identified as part of its
+ deliberations. These usecases and requirements are captured in this document to serve as a basis for
+ future work.
+ </p>
+ </section>
+
+ <section>
+ <h2>Access Control</h2>
+ <p>
+ Access Control is a mechanism through which an agent ( an HTTP server in this case ) permits other agents --
+ individuals, organizations, and/or groups made up of these -- to perform certain operations on resources as
+ specified by policies for the resources and for the agents . Within this document, the resources are LDP resources, but the access
+ control may operate at different granularities: RDF or other documents, named graphs, individual triples, or
+ individual attributes. The operations are create, read, update, and delete (CRUD).
+ </p>
+ <p>
+ When an agent requests a collection of resources it gets to see only those resources or parts of resources
+ it is authorized for.</p>
+ <p>
+ Depending on the granularity, the access control mechanisms may affect performance, but should not affect
+ semantics.</p>
+ <p>
+ For access control to come into play, the server must restrict some operations on some resources.
+ </p>
+ </section>
+ <section>
+ <h2>Terminology</h2>
+ <ul>
+ <li>ACG: An Access Control Graph describes which an agent or a group of agents can have some mode of access to a resource,
+ or collection of resources.</li>
+ <li>ACG Resource: A resource whose representation contains one or more ACGs which the server relies
+ upon to make access control decisions.</li>
+ </ul>
+ </section>
+ <section>
+ <h2>Usecases</h2>
+ <section>
+ <h3>Access Control on manipulation of resources via HTTP</h3>
+ Adam's user agent attempts:
+ <ol>
+ <li>To CREATE, READ, UPDATE (or PATCH), or DELETE a resource identified by a URL. The server may immediately
+ allow or deny the request, or it may request that he authenticate to confirm his privileges,
+ as specified the by the ACG for the Resource.</li>
+ <li>To UPDATE, CREATE or DELETE an attribute of the resource identified by the URL. The server allows or denies
+ the request as specified the by the ACG for the resource and attribute and whether fine-grained access control
+ is supported.</li>
+ <li>If he is denied access, an explanation of why all or part of his request was denied should be provided
+ so that it becomes possible to detect errors, and so that he may modify the request --
+ potentially to include making a request for such privileges.
+ </li>
+ <li>Adam would ideally like to know whether he will be able to perform an Action on a Resource
+ before attempting such - i.e., whether he will have to authenticate before he is able to Read or Write the Resource.
+ </li>
+ <ol>
+ </section>
+ <section>
+ <h3>Editability of Access Control Rules using HTTP</h3>
+ <ol>
+ <li>
+ Bart's user agent logs on to a server and requests:
+ <ol>
+ <li>The ability to read a group of related resources such as all the papers presented at a conference.</li>
+ <li>The ability to update an attribute of related resources, for example, to add a copyright notice to each resource.
+ </ol></li>
+ <li>Employees with job titles VP or SVP can sign (update) supplier contracts.</li>
+ <li>Charlie, the Webmaster, would like to grant read access to the papers presented at a conference to all the
+ people who attended the conference.</li>
+ <ol>
+ </section>
+ <section>
+ <h3>User Interface Scenarios</h3>
+ Eddie's HTTP based user agent would like to provide a user interface to allow, where possible, Eddie to
+ <ol>
+ <li>Know if he can edit or delete a resource.</li>
+ <li>Know what he would have to do to have access to a resource ( be someone's friend, be part of a club, have
+ paid a fee )</li>
+ <li>Allow Eddie to edit the access control rules for a resource such as:
+ <ol>
+ <li>Allow friends of his to access a document.</li>
+ <li>Allow friends of his to POST to a container, but only read a subset of the contents of the container,
+ those posted by that agent for example.</li>
+ <li>Allow all the members of the LDP WG to create and edit resources including LDP Containers under a
+ specific URL pattern.</li>
+ <li>Allow all friends of friends as expressed by the foaf:knows relations in one's foaf profile to POST comments
+ to a container related to some content, and edit their own comments.</li>
+ <li>Allow the members of the LDP WG, the RWW CG, the WebID CG, and the member of the European Ontologist Network,
+ to work together on set of ontologies. It should be possible to drag and drop URLs for these groups,
+ found on the web, onto the User Interface as a way of creating the union of the members of the group.</li>
+ </ol>
+ </ol>
+ </section>
+ <section>
+ <h2>Requirements</h2>
+ <ul>
+ <li>An Agent must be able to authenticate herself to a server with an identifier or as the owner of a token.
+ ( All use cases )</li>
+ <li>Ability to specify a collection of agents, identifying agents with URIs, URI patterns, or by description.
+ (Usecase 3.2.2, 3.2.3)</li>
+ <li>Ability to specify a collection of resources, identified by URIs or URI patterns or by description,
+ with a specified access policy. (Usecase 3.2.1, 3.2.3)</li>
+ <li>Ability to connect a collection of agents with a collection of resources with given access privileges.
+ ( All use cases )</li>
+ </ul>
+
+ The above requirements require the ability, by an authorized agent, to CREATE, EDIT, UPDATE relevant ACGs.
+
+ <ul>
+ <li>Ability to specify access privileges at a fine-grained level. (Usecase 3.1.2, 3.2.1.2)</li>
+ <li>The server should be able to describe access control policies for a resource. (Usecase 3.1.4, 3.3.1, 3.3.2)</li>
+ <li>The server should be able explain the reasons for access being disallowed in a machine readable format.
+ (Usecase 3.1.3)
+ </li>
+ <li>A user-agent should be able to find the ACG for a given resource.(Usecase 3.1.1)</li>
+ <li>The ability by one user agent to delegate the authority to create and edit ACGs to another agent.<(Usecase 3.3.3)/li>
+ </ul>
+ </section>
+ <section>
+ <h2>Outline of a Charter for a Access Control WG</h2>
+ <p>An Access Control Graph (ACG) consists of two kinds of collections: a collection of agents and a collection of
+ resources. It then connects a collection of agents with a collection of resources with the connection identifying
+ the privileges the agents have on the resources: CREATE, READ, UPDATE, DELETE.</p>
+ <p>ACGs are resources in their own right and can have access control priviledges specified for them just like
+ any other resource. This permits the creation and modification of ACGs to be delegated.
+ </p>
+ <p>
+ The members of the collection of agents contain tokens that the agents obtain from some authentication service.
+ The members of the collection of resources are URIs or URI templates.</p>
+ <p>The WG will need to decide whether it also wants to define fine-grained access control at an attribute level.</p>
+<section>
+<h2>Deliverables</h2>
+<ul>
+<li>Define the collections that are part of the ACG and define how a collection of agents is connected to a
+connection of resources.</li>
+<li>Define how ACGs can be created and edited and how these rights can be delegated.</li>
+<li>Describe a proof-of-concept implementation of how a request for access to a resource by an agent can be processed
+efficiently with the ACG structure defined above.</li>
+</ul>
+</section>
+ </section>
+ </section>
+
+
+ </body>
+</html>