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Re: How To Handle WebIDs for (X)HTML based Claim Bearing Resources

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Tue, 03 Jan 2012 12:14:26 -0500
Message-ID: <4F033772.3000707@openlinksw.com>
To: public-xg-webid@w3.org
On 1/3/12 10:51 AM, Mo McRoberts wrote:
> On 3 Jan 2012, at 15:33, Kingsley Idehen wrote:
>> On 1/3/12 10:18 AM, Mo McRoberts wrote:
>>> On 3 Jan 2012, at 15:12, Kingsley Idehen wrote:
>>>> On 1/3/12 10:06 AM, Mo McRoberts wrote:
>>>>> On 3 Jan 2012, at 14:32, Kingsley Idehen wrote:
>>>>>> On 1/3/12 9:21 AM, Mo McRoberts wrote:
>>>>>>> I can't actually parse most of this e-mail. Sorry.
>>>>>>> Kingsley, can you provide some pseudocode or _something_ which explains in a step-by-step fashion how you think an end-user and verifier should deal with this?
>>>>>> End-user: make a new certificate and update the WebID idp space.
>>>>> The point was: you don't have access to that space. Now what?
>>>> The point is: it doesn't matter. You have lost access to Blgospot or some other place to which a URI resolves, so what? You make a new certificate with pointers to a new idp space. In said space you make your claims. You visit a protected resource scoped to you old name, the verifier de-references pointers, and if smart, with comprehend the equivalence claim in the graph and understand this is the same referent.
>>> You need to be a little more clear about “with comprehend the equivalence claim in the graph and understand this is the same referent”. Are you assuming the new certificate is signed by the same key as the original was (which I suggested right at the beginning of this thread as a solution)?
>> No I am making no assumption about private keys. The only thing that's pivotal to WebID are the "mirrored claims" .
> Right. So:
> You lose access to Blogspot — there is now nothing WebID or Linked Data-shaped published there (or worse, there is, but it says something different to what you'd published). So, you create a new cert pointing at a new profile document which states that<new-URI>  owl:sameAs<http://kingsley.blogspot.com/>.
> How is that any different from _me_ creating a cert pointing at a new profile document which states that<my-URI>  owl:sameAs<http://kingsley.blogspot.com/>

When you sign the claim a verifier can apply WebID logic to it. 
Especially, when it already has record of your prior claim. This is what 
a proxy URI enables i.e., cache of prior claims (URI and Public Key 
relations) in an Idp space to which you have CRUD privileges.

<my-URI>  owl:sameAs<http://kingsley.blogspot.com/>

Will not work in this scenario. Where is the proof? The relation is<my-URI>  and a Public Key equivalent to<my-New-URI>  and a Public Key, in my idp space. It isn't just about the statement. There is a context to which these equivalence semantics are being applied.

Again, I am not mandating owl:sameAs without context of WebID. I am saying, in a nutshell, sign the owl:sameAs claim when its made in idp space. WebID lets you verify claims.

> What's the differentiating factor between ME doing it falsely (i.e., attempting to hijack your data stored in verifying parties’ systems) and YOU doing it validly (attempting to maintain access to your identity on those systems)?
>> Remember, losing a computing device that holds my private key has no impact on WebID verification  since a relation deletion (in idp space) nullifies its effects. Everything is about the Names and their relations, mirrored across the Cert. in the local key store and the relations graph in the idp space.
>>>   This does come with the caveat that the verifier stored the key in the first place.
>> Caching and invalidation schemes are part of the deal re. AWWW.  Our proxy URIs are cached and subject to cache invalidation rules when used in SPARQL queries, for instance.
>> I believe the easy path to understanding my point is to think about accessing a protected resource where the ACLs are based on a URI you no longer control. How do you make the claim: I am the same referent albeit for a URI based Name for which I've lost control?
> That's precisely the query I've been posing all along: how *do* you do that? (Although, in reality, it doesn't have to be an ACL, it's any situation where you wish to identify yourself to a verifying party). You claim to have a solution implemented, but I’m struggling to fathom precisely what it is.

We leverage cache. For added assurance you can sign each equivalence 
claim using your WebID, and then verify said statements about statements 
using WebID. A WebID verifier can make use of cache and cache 
invalidation schemes. Of course, that isn't mandatory, but its an 
engineering choice that an implementor can make. One we've made.

You can have an object/entity that has the properties: subject, 
predicate, object. Said object (a statement object) can also be endowed 
with other properties that include a signature, statement hash, and a 
cert. blob. Reification enables you to construct triples about triples. 
Thus, I can assert that "I" made a claim about my "Identity" via a given 
statement. You can even embellish further with provenance oriented terms 
using a provenance ontology.

Verifiable recall is part of the deal here albeit an WebID verifier 
engineering choice.

Remember, when I loose control over my URI (e.g. blogspot) I don't loose 
control over the local cert. in my keystore that holds the claims vital 
to WebID based verification. Thus, for a reified statement, I simply 
need to prove:

1. the claim creator had crud privileges in this idp space -- now with 
our verifier we have a cache of the WebID and Public key relations
2. the identity of the claim maker was verified when the claim was made 
-- a little bit of provenance added to the mix
3. a signature to that effect associated with the claim .




Kingsley Idehen	
Founder&  CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca handle: @kidehen
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LinkedIn Profile: http://www.linkedin.com/in/kidehen
Received on Tuesday, 3 January 2012 17:17:17 UTC

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