Embedded Metadata with XMP
http://wiki.creativecommons.org/XMP

XMP (eXtensible Metadata Platform) facilitates embedding
metadata in files using a subset of RDF. Most notably XMP
supports embedding metadata in PDF and many image formats,though it is designed to support nearly any file type.
Creative Commons recommends XMP as the preferred format
for embedded metadata, given its support for numerous fileformats and the balkanized state of embedded metadata
standards. Others are coming to a similar conclusion; Microsofthas announced support for XMP in Vista applications1 and JonUdell notes “There’s also good support in .NET Framework
3.0 for reading and writing XMP metadata.”2 Note that evenwhen embedded with XMP metadata, Creative Commonsrecommends a licensed document include a visible copyrightnotice. Format-specific recommendations for visible notices areavailable in the Creative Commons wiki3 .
The Creative Commons licensing process offers a XMP template
as part of the license selection process which may be used tomark files within XMP-supporting Adobe applications.

Specifying License Information

XMP defines a rights management schema4. Creative Commonssets the following properties:
xmpRights:Marked: Indicates this is a protected resource;
False if Public Domain, True otherwise.
xmpRights:WebStatement: The location of a web page
describing the owner and/or rights statement for this resource;
for example, http://example.com/pdf-metadata.html. Creative
Commons recommends this resource contain embedded,machine-readable metadata.
xmpRights:UsageTerms: An optional field describing legal
terms of use; Creative Commons recommends that whenpresent this take the form:
This work is licensed to the public
under the Creative Commons AttributionShareAlike license http://creativecommons.
org/licenses/by-sa/2.0/ verify at http://example.com/pdf-metadata.html(Replace URL following ‘verify at’ with URL containing
metadata about the XMP-embedded file; this is typically theURL specified by xmpRights:WebStatement.)

We also define a Creative Commons schema http://
creativecommons.org/ns# whose common prefix is cc. It
currently has the following properties:
license: The license URL; for example,
http://creativecommons.org/licenses/by-sa/2.0/.
morePermissions: A URL where additional permissions(commercial licensing, etc) are available. This URL should
typically be exposed in a “clickable” fashion, providing
publishers with an opportunity to drive traffic back to theoriginating site.
attributionURL: The URL to use when attributing this work.
attributionName: The creator’s preferred name to use when
attributing this work.

Verification Links and XMP

A publisher can add boost confidence in embedded metadata byproviding a verifying web statement. A verifying web statement isa URL which contains metadata with assertions matching thoseembedded in the file. The difference is that instead of making theassertions about a URL, the assertions are made in reference tothe SHA-1 hash of the file.
For example, the example web statement http://example.com/
pdf-metadata.html would include metadata encoded as RDFa.
<p>The document example.pdf is licensed
under a<a about=”urn:sha1:MSMBC5VEUDLTC26UT5W
7GZBAKZHCY2MD” rel=”license” href=”http://
creativecommons.org/license/by/3.0/”>
Creative Commons Attribution 3.0</a> license.
</p>

When processing a file containing an embedded web statement,an application can retrieve the statement and parse it foradditional metadata. If matching assertions are found which
apply to the calculated SHA-1 hash of the file, the application candisplay an indicator noting increased confidence in the metadata.
This approach has the added benefit of taking advantage of an
existing mechanism (copyright take-down procedures) in orderto break the confidence in the case of inappropriately licensed
material, thereby limiting liability.

CC and CC+ Overview for the World Wide Web

References[1] http://blogs.msdn.com/pix/archive/2006/08/23/715340.aspx[2] http://blog.jonudell.net/2007/02/14/
truth-files-microformats-and-xmp/[3] http://wiki.creativecommons.org/Marking[4] “XMP Specification (September 2005)”,
http://www.adobe.com/devnet/xmp/, Page 42

More Information
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