KeyInfo vocabulary

This RDF vocabulary provides terminology for describing key information, based on structures from XML Signature.

It defines classes and properties that correspond to a subset of the xmlsig-core RDF datamodel that was sketched as part of the W3C XML Digital Signature recommendation (2000, 2nd edition 200x).

We are concerned here purely with the 'key info' construct, and with reflecting into an RDF vocabulary just enough of the XML Signature concepts that we can associate X509 and PGP key data with other claims about the parties (whether personal, organizational, or something else) that hold them.

IMPORTANT: Please note that this work is purely speculative. Do not use it for anything beyond research activities. Feedback is welcomed via foaf-protocols@lists.foaf-project.org

Overview

The core concept here is 'KeyInfo'. XML Signature captures this in an XML element, and the suggested RDF representation included in the spec models this as a relationship between a "Signature" object and another object of un-named type. As we are only representing KeyInfo, rather than attempting a full expression of xmlsig in RDF, we will begin with an RDF class, "KeyInfo", and then pick up the suggested properties for this class directly from the xmlsig design.

The XML Signature diagram includes the following key:

(...) - anonymous node

blue - xml keyword

Element Attribute = - implicit element content

element/attribute - "literal"

This is not entirely clear. The diagram also contains indicative instance data, which helps give some sense of the intended design. These examples are elaborated upon here, for similar reason.

Vocabulary
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Open Issues

How much RDFS/OWL do we need to capture things more explicitly?

How do we say that a property can point to an XML element?

What additional considerations does an RDF environment bring? (eg. partial information, extensions, use of URIs/IRIs, whitespace handling; syntax-layer issues eg. GRDDL, N3, RDF/XML, RDFa, SPARQL, RIF)

Do we say anything about classes where URIs are expected vs bnodes? security/privacy aspects of parties identifying others by http URI? (HTTP logs etc. re privacy, plus usual http insecurities)

Appendix A: Raw Notes

The 2000 diagram provides only a rough indication of property names. These are extracted below.

keyInfo KeyName KeyValue SubjectName RetrievalMethod X509Data X509Issueserial X509SKI X509Name X509Certificate X509CRL PGPData PGPKeyID PGPKeyPacket