W3C home > Mailing lists > Public > public-prov-wg@w3.org > March 2012

Expiration (invalidation, destruction) of entities

From: Graham Klyne <graham.klyne@zoo.ox.ac.uk>
Date: Thu, 15 Mar 2012 16:36:47 +0000
Message-ID: <4F621A9F.6080304@zoo.ox.ac.uk>
To: W3C provenance WG <public-prov-wg@w3.org>
To recap and expand on some things said in the meeting:

(1) I think the chairs would be justified in retaining the proposal offered - 
nobody actually opposed it, some supported it.  It's just that many people 
didn't care enough.  It's good to make an attempt to gather stronger consensus, 
as long as it's not at the expense of more urgent goals.

(2) Thinking about the example of burned paintings (or deleted files?) - I think 
it makes more sense if there's a specific activity-entity association event 
after which the entity is no longer available.  It turns out that on closer 
examination, this is indeed what is proposed, but not what the introductory text 
seems to say.

Suggest:  "<Invalidation> is the start of the destruction or cessation of an 
existing entity by an activity.  The entity is no longer available for use after 
this <invalidation>."

What I've done here is mirrored the text used for "generation".

I think a somewhat compelling use-case is to be able to detect an inconsistency 
in data if a usage event occurs after a claimed destruction event.

My support for this proposal is now up to +0.5.  I can see why it could be 
useful, but I won't fall on my sword to protect it :)

...

I've just thought of a more compelling use-case: certificate expiry.  If a 
document is signed at time 't' using a certificate that expired at some time 
't-d', then the signature is not strictly valid.

If that's in scope for this feature, I'd fully support it.

#g
Received on Thursday, 15 March 2012 17:22:00 GMT

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