[Gzz] urn-5 "documents"

[Benja Fallenstein]

Re Tuomas' comment in urn5.tex, in the "Potential Problems" section.

You say, "Anyone may spoof an id easily. Therefore, you can't really 
refer to an id outside of the current context: too easy to substitute 
another document for it."

IMHO that's the wrong way to think about this. urn-5 ids *never* refer 
to specific data, there is no GET-type operation defined on them. If you 
use a urn-5 as the name of an HTML anchor, 
<http://example.org/myPage.html#urn:urn-5:abcde> does refer to specific 
data (you can load it and show it in a browser), but <urn:urn-5:abcde> 
does not. urn-5 URNs refer to a *concept* like e.g. a person, they never 
map to an actual file. <urn:urn-5:abcde> refers not to a specific anchor 
in a specific HTML page which you could retrieve, but is more like "the 
anchor created by Janne Kujala on 04/17/1998, 8:17:53." So the 
"spoofing" we can do here is on the level of taking a Xanalogical 
document and rearranging the letters to give a different meaning-- this 
generates false hits when links and transclusions are resolved, but it's 
not spoofing as in substituting a document in the place of another in a 
request.

- Benja