<remark><p>Per a vote of the XMPP Council, advanced specification from Experimental to Draft; simultaneously the XMPP Registrar issued a namespace of "urn:xmpp:pie:0".</p></remark>
<remark><p>Modified to include feedback received during the initial Last Call. Added sections for privacy lists and incoming subscriptions, as well as text on XInclude security.</p></remark>
<remark><p>Initial published version.</p></remark>
</revision>
<revision>
<version>0.0.1</version>
<date>2007-07-27</date>
<initials>mh</initials>
<remark><p>Initial version.</p></remark>
</revision>
</header>
<section1topic='Introduction'anchor='intro'>
<p>Different implementations of XMPP-IM servers store user data in various ways, and many implementations have more than one storage format. This leads to problems when a server administrator wants to switch to another implementation or storage format -- the implementation is as likely as not to have an import mechanism that can read the user data in its current form. This document attempts to solve that problem by defining a common file format for import and export of user data in XMPP-IM servers.</p>
</section1>
<section1topic='Requirements'anchor='reqs'>
<p>The following constraints are imposed on this standard:</p>
<ul>
<li>
<p>The file format is XML-based.</p>
<p>XMPP-IM servers already have tools to process XML data. This also allows extension of the format using namespaces. Furthermore, some of the data that needs to be stored is by definition already in XML form.</p>
<p>All user data is stored, but no server configuration data.</p>
<p>User data has similar form throughout the XMPP world, but server configuration is implementation-specific. Therefore this specification does not attempt to transfer any aspects of the server configuration from one server to another.</p>
<p>Furthermore, the contents of MUC, Pubsub and other services are out of scope for this specification.</p>
</li>
<li>
<p>Multiple virtual hosts are supported.</p>
<p>Many server implementations can serve several hostnames in a single server instance. Thus this specification allows storing data from several virtual hosts.</p>
<p>At any point in the file, an exporting server may put elements qualified by a namespace not mentioned in this specification. The exported data SHOULD be meaningful without the extensions. An importing server that encounters a namespace that it doesn't understand, or otherwise is unable to import all given data, SHOULD ignore the unknown data, SHOULD notify the operator, and MAY offer to terminate the process.</p>
<p>The child elements of the <server-data/> elements are <host/> elements. Each <host/> element describes a virtual host, and has a 'jid' attribute that contains its JID.</p>
<p>An importing server MAY automatically adjust its list of virtual hosts to fit the ones present in the data being imported. If it does not, it SHOULD notify the operator about any mismatch.</p>
<p>Each user is represented by a <user/> element under the <host/> element. The <user/> element MUST have a 'name' attribute, which contains the node part of the user's JID.</p>
<p>If the plaintext password of the user is known, it MAY be included in the 'password' attribute, although this is not recommended from a security perspective. For more information see <linkurl='#security'>Security Considerations</link>. See also the SCRAM credentials section for an alternative.</p>
<p>Authentication secrets may be included that allow for authentication using the SCRAM family of mechanisms, as defined in &rfc5802;.</p>
<p>Each set of credentials should be encapsulated within a <scram-credentials/> element in the 'urn:xmpp:pie:0#scram' namespace, and contained within the relevant <user/> element. The element should have a 'mechanism' attribute specifying the registered name of the mechanism that the credentials are used for (always without the "-PLUS" suffix), e.g. 'SCRAM-SHA-1'. The element MUST contain a single occurrence of each of the following child elements:</p>
<ul>
<li><iter-count/>: containing the SCRAM iteration count, e.g. '10000'. This must be a positive integer without leading zeros.</li>
<li><salt/>: containing the base64-encoded salt.</li>
<li><server-key/>: containing the base64-encoded ServerKey defined by SCRAM.</li>
<li><stored-key/>: containing the base64-encoded StoredKey defined by SCRAM.</li>
</ul>
<p>There may be multiple occurrences of <scram-credentials/> for a single user, however they MUST all have a unique 'mechanism' attribute.</p>
<examplecaption='Including a user's SCRAM credentials'><