- From: Dan Brickley <danbri@w3.org>
- Date: Sat, 1 Dec 2001 21:35:06 -0500 (EST)
- To: Tim Berners-Lee <timbl@w3.org>
- cc: "Sean B. Palmer" <sean@mysterylights.com>, Dan Connolly <connolly@w3.org>, <www-archive@w3.org>
On Fri, 30 Nov 2001, Tim Berners-Lee wrote: > > The properties that one can use at the moment are:- > > > > crypto:md5 a rdf:Property; rdfs:label "md5"; > > rdfs:comment "The MD5 hash of a string"; > > rdfs:domain string:String; rdfs:range string:String . > > > > crypto:sha a daml:UnambiguousProperty, > > daml:UniqueProperty; rdfs:label "sha"; > > rdfs:comment "The SHA hash of a string"; > > rdfs:domain string:String; rdfs:range string:String . > > I notice your higher trust of sha1! I've been using a sha1 property too, to talk about photos, MP3s, MPEG video content etc indirectly. Agonized a bit about whether it was really a daml:UnambiguousProperty, decided it wasn't. Toying with using a utility class like FOAF:NearAsDammitUnambiguousProperty, since such info would be useful for query planners, database indexes etc. The only other thing I could think was to just baldly assert that util:sha1 _is_ unambiguous, and make sure the defintion gives some account of which bag-o-bytes is the 'right' one, for the astronomical nitpicky case where two chunks of data have the same sha1. Kind of use I have in mind is a little different... but wonder if a single schema would serve both apps: <foaf:Work> <dc:title>Some Movie's Title</dc:title> <foaf:encodedPart> <foaf:Document dc:size="691423423424" dc:format="video/mpg" foaf:partNo="1" digit:sha1="3ffbecf36520245ecb6aff020a3etcetcetc"/> <!-- rights management metadata goes here... --> </foaf:encodedPart> <...etc> Wonder what cwm would do if you found two strings that had the same sha1... Dan
Received on Saturday, 1 December 2001 21:35:08 UTC