Chemical Markup, XML, and the World-Wide Web. 3. Toward a Signed Semantic Chemical Web of Trust

We describe how a collection of documents expressed in XML-conforming languages such as CML and
XHTML can be authenticated and validated against digital signatures which make use of established X.509
certificate technology. These can be associated either with specific nodes in the XML document or with the
entire document. We illustrate this with two examples. An entire journal article expressed in XML has its
individual components digitally signed by separate authors, and the collection is placed in an envelope and
again signed. The second example involves using a software robot agent to acquire a collection of documents
from a specified URL, to perform various operations and transformations on the content, including expressing
molecules in CML, and to automatically sign the various components and deposit the result in a repository.
We argue that these operations can used as components for building what we term an authenticated and
semantic chemical web of trust.