W3C home > Mailing lists > Public > public-webid@w3.org > April 2013

Re: Domain of :key

From: Dominik Tomaszuk <ddooss@wp.pl>
Date: Mon, 01 Apr 2013 15:12:12 +0200
Message-ID: <515987AC.50008@wp.pl>
To: Melvin Carvalho <melvincarvalho@gmail.com>
CC: Henry Story <henry.story@bblfish.net>, Mo McRoberts <Mo.McRoberts@bbc.co.uk>, public-webid <public-webid@w3.org>
01.04.2013 14:57, Melvin Carvalho:
>
>
>
> On 1 April 2013 09:39, Henry Story <henry.story@bblfish.net
> <mailto:henry.story@bblfish.net>> wrote:
>
>
>     On 1 Apr 2013, at 01:55, Mo McRoberts <Mo.McRoberts@bbc.co.uk
>     <mailto:Mo.McRoberts@bbc.co.uk>> wrote:
>
>      >
>      > On Sun 2013-Mar-31, at 20:33, Henry Story
>     <henry.story@bblfish.net <mailto:henry.story@bblfish.net>>
>      > wrote:
>      >
>      >> No, it is a thing that does stuff. There is no problem with
>     calling your web server an agent.  Browsers are called user agents,
>     presumably because there are server agents. There is a whole field
>     of programming called agent oriented programming.
>      >
>      >>> Similarly, I have applications which have their own client
>     certificates for communicating with servers: these are issued
>     specifically to the application so that it can authenticate
>     autonomously with an identity which is deliberately distinct from
>     any human involved in its development and operation. Again,
>     describing a webapp as a foaf:Agent strikes me as dubious stretching
>     of the term 'agent', there (compared to, say, an application which
>     is operating under the "direction" of an operator).
>      >>
>      >> No there is no problem with that. foaf:Agent is more general
>     that human agents, and so you can give a webid to a software
>      >> agent and relate it via the cert:key to a public key. No problem.
>      >
>      > If you ascribe foaf:Agent to everything which has some property
>     which means it may at some point fall within the definition given,
>     then you end up applying foaf:Agent to pretty much everything…
>
>     You should discuss that with Dan Brickley on the foaf mailing list
>     if you think his definition is
>     so close to being a owl:Thing that it's not worth having the
>     distinction.
>
>     We don't assign the domain of :key or the range of :identity to any
>     agent, but to those
>     for which the following is true:
>
>     :identity a rdf:Property, owl:ObjectProperty;
>          vs:term_status "archaic";
>          rdfs:label "identity"@en;
>          rdfs:isDefinedBy <cert#>;
>          skos:editorialNote """
>               It turns out that this relation is unintuitive to write
>     out and to name.
>               One should instead use cert:key
>          """@en;
>          rdfs:comment """
>          the identity of the public key. This is the entity that knows
>     the private key and
>          so can decrypt messages encrypted with the public key, or
>     encrypt messages that can
>          be decrypted with the public key.
>          """@en;
>          owl:inverseOf :key;
>          rdfs:domain :PublicKey .
>
>
>     That is it has to be something that can be responsible for a private
>     key - keeping
>     it safe from other agents within reason, and it has to be something
>     that can encrypt
>     and decrypt messages with the key. Those are very clearly agent like
>     things.
>     Software agents can be such things.
>
>      >
>      > This is the distinction, I guess, between 'is defined as an
>     agent' and 'has the properties of an agent' — and I suppose why
>     X.509/LDAP has a distinction between 'structural' and 'auxiliary'
>     classes (the former being defining qualities, the latter describing
>     facets).
>      >
>      > What about, say, a piece of digital media? There are situations
>     where encoded media has its own keys conforming otherwise to the
>     ontology, and it's a bit of a stretch to say that *it* is an agent.
>
>     Does digital media also have its private keys with which it can sign
>     something? Is Holloywood going to
>     encrypt digital media and add the private key to the media too, so
>     that the media can then do what?
>     Clearly not. So they don't conform to the ontology
>
>     But perhaps this will become more obvious if you give us the use
>     case. My guess is that this
>     will reveal that you need a very different relation. And I am not
>     against that.
>
>      >
>      > Flipping this around the other way, why _should_ the domain be
>     restricted to foaf:Agent? What practical problems does it cause?
>     (Noting that this isn't necessarily modifying the definition of a
>     WebID, just that anything can have a key or even a certificate
>     associated with it).
>
>     Because we want a relation relating the Agent that is doing the
>     encryption decryption using the given key.
>     We have been using that since the beginning of WebID.
>     Other relations are possible, and it is easy to create new ones if
>     needed.
>
>
> This is interesting logic so you want one relation that relates a key to
> a URI and one that relates a key to an agent.  Logically they should be
> named something like "key" and "agentKey", right?  The downside of this
> suggestion is that implementations would need to change.
>
> Though I think we have consensus slightly in favour rdfs : Resource
In which point rdf:Resource is better than owl:Thing? I do some ontology 
state-of-the-art and I don't see too much ontologies with uses 
rdfs:Resource in rdfs:domain or rdfs:range. My conclusion to these 
aproaches is that rdfs:Resource is used in low-level ontologies and cert 
ont isn't in that level. Probably better consensus is owl:Thing.
Of course, I don't change my mind and I still think that foaf:Agent is 
better.

D.

>
>
>
>      >
>      > M.
>      >
>      > --
>      > Mo McRoberts - Analyst - BBC Archive Development,
>      > Zone 1.08, BBC Scotland, 40 Pacific Quay, Glasgow G51 1DA,
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-- 
Dominik Tomaszuk
Research Fellow
University of Bialystok
Poland
Received on Monday, 1 April 2013 13:12:39 UTC

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