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

Re: Domain of :key

From: Melvin Carvalho <melvincarvalho@gmail.com>
Date: Mon, 1 Apr 2013 15:17:12 +0200
Message-ID: <CAKaEYh+40-qUJhL9kBvFM9N5CbDbb2eYAtMN+K4Y6SoM1zGPmA@mail.gmail.com>
To: Dominik Tomaszuk <ddooss@wp.pl>
Cc: Henry Story <henry.story@bblfish.net>, Mo McRoberts <Mo.McRoberts@bbc.co.uk>, public-webid <public-webid@w3.org>
On 1 April 2013 15:12, Dominik Tomaszuk <ddooss@wp.pl> wrote:

> 01.04.2013 14:57, Melvin Carvalho:
>
>>
>>
>>
>> On 1 April 2013 09:39, Henry Story <henry.story@bblfish.net
>> <mailto:henry.story@bblfish.**net <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<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.
>

Good point, actually foaf uses owl : Thing


>
> D.
>
>
>
>>
>>
>>      >
>>      > M.
>>      >
>>      > --
>>      > Mo McRoberts - Analyst - BBC Archive Development,
>>      > Zone 1.08, BBC Scotland, 40 Pacific Quay, Glasgow G51 1DA,
>>      > MC3 D4, Media Centre, 201 Wood Lane, London W12 7TQ,
>>      > 0141 422 6036 (Internal: 01-26036) - PGP key CEBCF03E
>>      >
>>      >
>>      >
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>>
>>     Social Web Architect
>>     http://bblfish.net/
>>
>>
>>
>
> --
> Dominik Tomaszuk
> Research Fellow
> University of Bialystok
> Poland
>
Received on Monday, 1 April 2013 13:17:42 UTC

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