CC0 Technical Overview

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Revision as of 20:15, 7 January 2008 by Nathan Yergler (talk | contribs) (Examples)
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CC∅ provides a framework that enables people to

  • (a) ASSERT that a work has no legal restrictions attached to it, OR
  • (b) WAIVE any rights associated with a work so it has not legal restrictions attached to it

This page describes the metadata used to describe these two complementary paths along with suggestions for publishers who wish to use CC∅.


CC∅ introduces two new terms in the Creative Commons namespace.

  • assertedBy: The URI of the actor asserting that a work is free of legal restrictions.
  • waivedBy: The URI of the actor (rights holder) waiving all legal rights to a work.


The CC∅ application returns HTML with embedded metadata describing the role the user has selected, along with any additional metadata provided. For example, a user waiving all rights to a work:

<p about="">
<a rel="license"
   href="" style="text-decoration:none;">
   <img src="" border="0" alt="CC0" /></a>
<br/>To the extent possible under law, <a rel="cc:waivedBy" href="">
<span about="" property="dc:title">A. User</span></a> has <a rel="license"
all copyright, moral rights, database rights, and any other rights that 
might be asserted over <a href="">Brilliance Described</a>. 

Described in N3, the triples encoded in the above HTML are:

<> <> <> .
<> <> <> .

<> <> "A. User" .

As you can see, this metadata makes statements about both the work and the person waiving their rights over the work.

Alternately, a user asserting that a work is free of legal restrictions:

<p about="">
  <a rel="license"
     href="" style="text-decoration:none;">
     <img src="" border="0" alt="" />
  <br/><a rel="cc:assertedBy" href="">
<span about="" property="dc:title">F. Bar</span></a> asserts 
<a href="">Brilliance Described</a> is 
<a rel="license"
    of any copyrights</a>. 

Described in N3, the triples encoded in the HTML above are:

<> <> <> .
<> <> <> .

<> <> "F. Bar" .


Creative Commons recommends marking works published under CC∅ with embedded metadata. Metadata allows search engines and web software to find structured information about pages. The minimal recommended case is specifying CC∅ as the license. Note CC∅ is not a license but provides similar information regarding re-use rights. Therefore we reuse the existing, supported infrastructure.

For example:

All legal rights to this page have <a rel="license" 
href="">been waived</a>.

Additional metadata may be specified using the assertedBy or waivedBy predicates. Each specifies a URI; publishers are encouraged to provide additional metadata about the actor at that location.