================= What's urn-5 for? ================= :Authors: Benja Fallenstein, Tuomas J. Lukka .. contents:: ABSTRACT ======== Our research group has recently registered the informal {\tt urn-5} namespace with IANA. We discuss the rationale behind the namespace and possible applications of this open namespace. Introduction ============ Starting more generally with identification, and then about how globality has become important now that the net makes places around the world accessible. - snailmail addresses - IP addresses - DNS - email addresses - URLs - X.400 - Digital signatures - freenet IDs - URN URN namespaces ============== ALL OTHER CURRENT URNs ARE CLOSED NAMESPACES?!?! http://www.iana.org/assignments/urn-namespaces EXCEPT urn:sha WHICH IS NOT OFFICIAL If you have a domain name, you can use urn:NewsML:, and the urn:tag: currently submitted to IESG for publication as an RFC. However, these aren't "open" namespaces as in "algorithmic." -- A good page to find info about urn namespaces is http://uri.net/urn-nid-status.html . **And** you need a domain name, which has all the problems of hierarchy, DNS abuse etc. Should we go through all the urn types briefly? The ``urn:urn-5:`` namespace ============================ CONTENT-ADDRESSABILITY AND POINTING: THE TWO COMPLEMENTARY OPERATIONS "I want the newspaper article whose hash is 239273498275" "I want to know what articles are in today's newspaper" You mean, talking about the idea that all user-meaningful "objects" (Ted's items...), like documents, paragraphs, vector graphics shapes etc. get a global identity the moment they're created, allowing to talk about them in a globally unique way? That sounds interesting. Could relate this to the Semantic Web (how you're able to make RDF statements about these things, e.g. metadata). Talk about how it gets rid of context problems (the id stays the same when moving the object to a different document) and possibly, how this allows for Ted's transclusions and links (links can be implemented using RDF and RDF search engines, which are in development). Can then relate it to zzstructure (editing textual XML with these identifiers is possible, but no fun; with a structural editor, like a zzstructure client, the ids can remain hidden). One really important point: non-hierarchy. Cite some of the DNS troubles, muscling of individuals by large corporations etc. Yes. Along with discussing the difference between this and urn:sha-1 really carefully. (Between this and "identification schemes based on secure hashing, such as the (unregistered) Freenet URIs": urn:sha-1 is neither used nor registered nor in the process of being registered, so the most we could refer to it is as an idea someone has had at some point. A nit, I know, but important when publishing this.) Possible order of presentation: - Globally unique ids and why you want to use them - Places that don't use globally unique ids currently, and what you cannot do because of that - The urn:urn-5 namespace - how it works - how it's different from hashing - Caveat: Human readability/writability problems - only in text editors, structure editors can handle ids internally - Caveat: unlike relative identifiers, when you have an urn:urn-5 id, you don't automatically have any document/context it appears in - when an anchor is removed? Applications ============ - you can have a central registry on a system containing those ids, if you want to perform lookups using them - this kind of registry would allow RDF statements about identified objects to be resolved - could use this to implement transclusions and links - Conclusions - RDF - HTML anchors - HTML/XML element ids - relative URIs, fragment identifiers - GNOME monikers Some are not globally unique, which is important to us because they're used in places where urn-5 could be used for unique identification. (Btw, JXTA ids may also be worth looking at.) Potential problems ================== Potential problem: someone makes program that assigns urn-5s badly, to create havoc. This problem is really no different from the corresponding one with digital signatures: you have to trust the software you use. Another: no way to verify an index. Anyone may spoof an id easily. Therefore, you can't really refer to an id outside the current context: too easy to substitute another document for it. Coupling urn-5 with digital signatures? Conclusion ==========