W3C home > Mailing lists > Public > public-xg-webid@w3.org > January 2012

Re: Certificate Triplify Challenge

From: Mo McRoberts <mo.mcroberts@bbc.co.uk>
Date: Wed, 4 Jan 2012 15:05:43 +0000
Cc: Jürgen Jakobitsch <j.jakobitsch@semantic-web.at>, public-xg-webid@w3.org
Message-Id: <91257A26-C269-4236-849F-69F2C3833DFD@bbc.co.uk>
To: Henry Story <henry.story@bblfish.net>

On 4 Jan 2012, at 13:50, Henry Story wrote:

> As soon as you put things this way you realise that it is wrong in fact. Because the above fails to make the point that it is the Certificate that is making the agent claims. What is really needed there is to use N3 to express what is going on:

Hmm, are you sure? Is it not that the certificate *carries* the claims made by the issuer?

If the purpose of the ontology is to allow round-tripping (which it must, IMO, so that you can verify the signature on the content — otherwise you might as well just have a lump of arbitrary signed RDF and forget about bothering with X.509's structure), then you have to be careful about how far you diverge from it, and that includes additional statements (which from a processor's perspective are just unsigned additional junk, like a comment header field in a PEM-formatted blob).

> then one realises that the MUST understand stamens are statements about grammar changes: they are saying that you cannot believe anything else about what you see in the document unless you understand one statement: i.e., that statement could possibly change the meaning of the other statements seen up to then. 

Yes… the criticality aspect of extensions falls into this category, although in X.509-land the rules assume that you do know how to process “an extension” in general and where to find the criticality field at a minimum — so with an RDF equivalent you could work on the same basis (i.e., you recognise cert:critical, and if it's set and you don't understand one of the classes associated with the extension, fail).

M.

-- 
Mo McRoberts - Technical Lead - The Space,
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Received on Wednesday, 4 January 2012 15:06:16 GMT

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