- From: David Chadwick <d.w.chadwick@kent.ac.uk>
- Date: Sat, 11 Jun 2016 16:58:09 +0100
- To: public-credentials@w3.org
On 11/06/2016 12:44, Timothy Holborn wrote: > The use-case for verifiable claims would make more sense if it were > about one credential that said someone has a passport with the name of > joe smith on it, and another with the name frank n. beans > > a verifiable claim needs to link to an identity. I would rather say that a verifiable claim identifies an entity (as maybe belonging to a group) but it does not necessarily identify a single unique individual. e.g. a ginger hair credential identifies the holder as a ginger haired person. regards David we haven't figured the > identity piece out yet, from memory, it was out of scope when > establishing the cred's. CG. > > Tim.H. > > On Sat, 11 Jun 2016 at 21:29 David Chadwick <d.w.chadwick@kent.ac.uk > <mailto:d.w.chadwick@kent.ac.uk>> wrote: > > > > On 11/06/2016 01:01, Steven Rowat wrote: > > Dave, > > Interesting reply. My responses throughout. > > > > On 6/10/16 12:54 PM, Dave Longley wrote: > >> On 06/10/2016 12:57 PM, Steven Rowat wrote: > >>> On 6/10/16 8:54 AM, Dave Longley wrote: > >>> > >>>> This is an "Identity Profile": > >>>> > >>>> { > >>>> "id": "<id from the identifier registry>", > >>>> "type": "Identity", > >>>> /* ...attributes asserted in this particular profile */ > >>>> } > >>>> > >>>> Note that the document above is referred to as an "Identity > Profile", > >>>> but the "type" associated with the "id" is "Identity". You can have > >>>> many > >>>> "Identity Profiles" for any particular "id", but the thing the > >>>> attributes therein are talking about is of type "Identity". > >>>> > >>>> > >>> > >>> I don't think I understand this difference yet, unless there > also exist > >>> instances that are not "Identity Profiles", yet also have an 'id', > >>> and a > >>> type: 'Identity'. Otherwise, why not just call the "type" for > "Identity > >>> Profile"..."Identity Profile" ? > >>> > >>> If this is true, can you give an example of one -- something > that isn't > >>> an Identity Profile, but would use the type: "Identity"? > >> > >> I think that's the wrong question. This is about what the identifier > >> identifies. In my opinion, it does not identify a Profile, it > identifies > >> an Identity. > > > > Ah, that's what I'm getting at. I need an example that shows me > how this > > works; and having read your whole answer (below, where I comment > more), > > I'm still fuzzy on whether this is true. > > > > Let me try an example another way: if it's true...then, if I make two > > profiles for real-life person John, both pseudonyms: > > > > The Alfred Identity Profile > > The Bob Identity Profile > > > > then, according to what you've said, the Alfred Profile and the Bob > > Profile will both have exactly the same id; that is, in the same > part of > > the code, each of the Alfred and Bob Profile will actually have the id > > of John from the identifier registry: > > > > Alfred Identity Profile contains: > >>>> "id": "<id [of John] from the identifier registry>", > >>>> "type": "Identity", > > > > Bob Identity Profile contains: > >>>> "id": "<id [of John] from the identifier registry>", > >>>> "type": "Identity", > > > > Is this true? > > It would appear to be so from the cat example that Dave gave (that > unfortunately has been cut out of your reply), in which the cat has two > different profiles but the same ID (because it refers to the same cat). > I think this is the wrong design, because we have now created > linkability between two separate profiles (or pseudonyms) that I might > have sent to two different relying parties. By using a common ID for two > different identity profiles we produce a correlation handle for the > relying parties. > > Your later conclusion that the IDs should be different seems to be right > approach to me, but this conflicts with Dave's approach > > regards > > David > > > > > If so, yes, I did misunderstand that. I thought the id was identifying > > the "Alfred Identity Profile" or the "Bob Identity Profile". So they > > could be distinguished from each other, and thus pretend to be > separate > > people (as far as the rest of the world knows). > > > > But...then, where does the id for the "Alfred Identity Profile" > sit? An > > id that distinguishes it as a separate thing in the universe? And > > especially that distinguishes it from the Bob Identity Profile. Those > > two ids must be somewhere, right? > > > > > >> It always takes something else (e.g. a document) to be able to talk > >> about an actual thing. A thing itself is the thing, it is not the > >> description of the thing. > > > > Yes, I don't think that was the source of my confusion. I may be > wrong, > > but I think the source of the confusion -- in addition to what I > > described above -- is the unfortunate coincidence (to the degree that > > it's a true coincidence, which is debatable I believe) of using > > identifiers, called "id" in the code, to identify everything including > > this thing human beings like to call "identity". Any statement that > > attempts to identify identity using identifiers is ripe for a > descent in > > to infinite loops at the least misstep. ;-) > > > > Maybe that's a strong argument for using 'entity' throughout > rather than > > 'identity', and I think I'd change my voting if I'd realized this > > earlier. Then we could be talking about 'id' and 'identifiers' of > > entities, not of identities. Which I, for one, would find a lot easier > > to follow. :-) > > > > > >> The statements within a profile associate information with an > Identity, > >> such as what it is, its "type". So the "type" does not refer to the > >> profile document, it refers to the thing you're talking about. > > > > I'm having trouble here. What is the referent for the first 'it', in > > 'what it is'? Is it 'Identity' or is it 'information'? > > > > What you seem to be saying is that the 'type' attribute doesn't > refer to > > the profile document, it refers to the 'Identity'. But the example you > > gave literally says type: "identity". So you're saying the > identity, the > > thing you're talking about, has a type which is 'identity'. But > this is > > tautological. > > > > I.e., how can there possibly be an Identity that has another type? An > > Identity that has a type...--oh, wait. Could there be an identity that > > has a type "pseudonym"? Hmm... > > > > > >> The profile document is just a collection of statements *about* the > >> thing. > >> It is a (typically incomplete) description of the thing. > > > > Right, but as above, where is the id that identifies the profile > > document, which represents a (possibly) pseudonymous identity? > > > > > >> Let's talk about "profiles" using something other than "Identity". > > > > Yes!!! :-) > > > > Or, alternatively, change the code so it uses something instead of > > 'identifier'. > > > > Like 'la' = 'label', instead of 'id' = 'identifier'. That would also > > remove the confusion with Identity as it is commonly used. This > may seem > > like a long way around, but maybe not. Since the core reason for > the VC > > to exist is to nail down 'Identity' as it is known globally and in the > > UN, then, using a term internally in the code that refers to > everything > > that can possibly exist in the world, real or virtual, with a code > term > > using a word, 'id' = 'identifier', that can be easily confused > with the > > word 'identity' (and probably will be by all the naive developers and > > users of the final system) seems to be asking for trouble. > > > > > >> And that would be a different "profile" of the same cat. If you > wanted > >> to give these "profiles" their own identifiers, you could do that as > >> well, but they would each get their own -- because they are different > >> things -- and because they are different from the cat itself. > > > > Agreed, see above. I was expecting this. > > > >> Similarly, people may create "identities" for themselves. You may > have > >> one that you use for work, one for home life, one for your medical > >> records, whatever. > > > > Yes, I was expecting this also, and, ah, now I think I finally see: > > > > In my example earlier of John's two pseudonyms, Alfred and Bob, I was > > not right. > > > > What actually happens is that Alfred and Bob are *pre-registered* with > > ids, before anything else can happen. Then: > > > > Alfred Identity Profile contains: > >>>> "id": "<id [of Alfred] from the identifier registry>", > >>>> "type": "Identity", > > > > Bob Identity Profile contains: > >>>> "id": "<id [of Bob] from the identifier registry>", > >>>> "type": "Identity", > > > > So: > > 1. Neither contain a John id. > > 2. And the id they do contain doesn't refer to the Profile > document itself. > > 3. And the Alfred Identity Profile, as a document, can have its own > > id...somewhere. Which you've probably already told me about in your > > reply by this time. :-) > > > > What fun language is. :-) > > > > Steven > > > > > > > > >
Received on Saturday, 11 June 2016 15:58:37 UTC