W3C

- DRAFT -

Verifiable Claims Working Group

06 Aug 2019

Agenda

Attendees

Present
Amy_Guy, Andrei_Sambra, Benjamin_Young, Daniel_Burnett, Dave_Longley, Dudley_Collinson, Manu_Sporny, Matt_Stone, Oliver_Terbu, Ted_Thibodeau, David_Chadwick, Sercan_Kum, Brent_Zundel, Jonathan_Holt, Justin_Richer, Yancy_Ribbens, Kaliya_Young, Kaz_Ashimura, Ganesh_Annan
Regrets
Chair
Dan_Burnett, Matt_Stone
Scribe
rhiaro, DavidC, dlongley, manu, burn

Contents


<rhiaro> scribenick: rhiaro

<stonematt> Zakim who's here

Agenda

burn: issues and PRs first, then test suite
... dmitri gave me a test suite update
... will spend the majority of the time on implementation guide and use cases doc
... This is already in the agenda, I have two items I needt o add
... one is we need talk about the DID WG creation vote, I suggest that after the issues
... Another is the UK gov's call for evidence which DavidC will present. I propose we do that after implementation guide discussion
... Want to limit the time on that.
... Any suggestions for changes?

DavidC: I've written a draft ?? for mdl and we've got a discussion tomorrow, I sent an early copy to manu and dave to ask them to look at the @context, I didn't circulate it to the group because I thought it was premature, but I will do so after tomorrow's meeting

PRs

burn: Going to look at PRs

<manu> https://github.com/w3c/vc-data-model/pulls

burn: manu just submitted a PR

<manu> https://github.com/w3c/vc-data-model/pull/708

manu: it's to address the only outstanding issue we have, Ted raised issue 704 which was that people can get mixed up if they copy and paste the examples
... I found some css magic that makes it so when you highlight the examples the css that's been added to the PR makes it so that the comments are not copied
... you can literally select everything, copy and paste it into somewhere else and thes tuff that's pasted is without the comments and the ...s
... you can't copy the comments now in the spec
... I also updated some of the accessibility for the comments and highlighted code, comments are now high contrast blue to meet accessibility guidelines, highlights are in high contrast green
... the one thing I did not do ted is point out the fact that the json contains comments, the only way that someone is going to get those comments in is either they're using a browser more than a decade old or they hand type the examples into something
... so I don't know if you still feel like we need to point ou tthat the json in the examples have comments in there that you shouldn't copy meaning it would be invalid json
... it's easy to add it, just don't know if we need to

TallTed: browsers are not the only way peopel will interact with this. I turn specs into pdf or print them out. THere are multiple paths here

manu: it's not a big deal, I'll add the text to the PR
... as soon as I add that text I'll make it a real PR

TallTed: there's no way to preview this before it gets merged because of the way this system works. It sounds good

manu: I have a preview link

<manu> here is the preview link: https://pr-preview.s3.amazonaws.com/w3c/vc-data-model/pull/708.html

<manu> https://pr-preview.s3.amazonaws.com/w3c/vc-data-model/pull/708.html#example-1-a-simple-example-of-a-verifiable-credential

TallTed: so now if someone wants to copy the comments there's a new problem

manu: the question is which problem can we live with
... there's that PR
... that addresses the only outstanding issue, as long as everyone is happy

oliver: if you scroll down to the jwt section there is a ... in quotes that gets highlighted

manu: I can fix that. Is the ... not supposed to be there?

oliver: it's supposed to be a base64 encoded string

manu: I'll look at that. Anything else?
... Only example 30 needs to be fix

stonematt: nor Safari

manu: gaaaahhhh css
... I'll fix for all browsers

burn: anything else on this issue?

Issues

burn: I believe the only issue we have left not deferred is the one we were just discussing
... so we're working on 704
... any objections to moving on?

DID WG creation vote (Manu) https://www.w3.org/2002/09/wbs/33280/did-wg-2019/

manu: great news is the DID WG charter is out for formal vote at the w3c. This is public. They announce charter votes now on a public mailing list, and request public comment on the charter as well
... What we need to do is clearly communicate with as many W3C members, specifically AC reps, that we vote in support of the charter. Right now with 0 notification we have 12 positive votes. We need 25, and the closer we get to 40 or 50 the better things will be
... I'm planning on contacting a veyr large subset of W3C AC members who wanted to be let know when the vote goes out
... It's really imporatn we do that before the end of the month, that's when we need to get as many votes as we can in
... if there are companies that we know support the work but are not yet W3C members and probably never will become them, they shoudl still send in an email stating that their company really wants this work to happen

<scribe> scribenick: DavidC

<manu> https://lists.w3.org/Archives/Public/public-new-work/2019Aug/0000.html

Manu asks that we broadly circulate the public announcement for the DID new work item

and asks everyone to ask companies they know to vote in support of it with W3C

All the public comments are very positive. There is just one invisible (probably negative) comment

The vote stops at the end of August

<manu> https://www.w3.org/2019/08/did-wg-charter.html

<manu> https://www.w3.org/2002/09/wbs/33280/did-wg-2019/results

Still determining who the second chair of the WG will be. Dan will be one

Test Suite Issues and Discussion

<burn> https://github.com/w3c/vc-test-suite/issues

Dan updated the status of the test suite and reports

Andre asked if the implementation reports could link to a repo with the code used for the testing

<burn> DavidC: we have passed all the tests, still need to update the test report

Implementation Guide

<burn> https://github.com/w3c/vc-imp-guide/issues

<deiu> https://github.com/w3c/vc-imp-guide/pulls

<deiu> https://github.com/w3c/vc-imp-guide/pull/18

<manu> +1 to merge.

Andrei said this PR can be merged

No objections to this

<manu> +1 to merge.

<deiu> https://github.com/w3c/vc-imp-guide/pull/19

<Zakim> manu, you wanted to request we setup github preview...

Oliver asked if we can set up Preview on github

<burn> ACTION: Kaz/chairs to set up PR previews on https://github.com/w3c/vc-imp-guide

Manu thinks the JWT text is broadly ok to merge (with only minor nit picks)

Oliver has to resolve conflicts before the text can be merged

<deiu> Last PR -- https://github.com/w3c/vc-imp-guide/pull/17

<deiu> https://github.com/w3c/vc-imp-guide/issues

DavidC said he will review the schem PR

<deiu> https://github.com/w3c/vc-imp-guide/issues/16

schem -> schema

<deiu> https://github.com/w3c/vc-imp-guide/issues/8

<manu> +1 to defer until Oliver's PR is in

<deiu> https://github.com/w3c/vc-imp-guide/issues/4

manu: Question was how to link to external resource from a VC
... use a cryptographic hash of some kind. Hashlinks is one (but not only) way

scribenick: burn

DavidC: thought this was about referencing a VC within another VC
... thinks you can just use the VC id

<Zakim> manu, you wanted to say that it's the same problem.

scribenick: DavidC

Manu: VC id on its own is not good enough because the contents at that link could change
... so need to either base64 encode OR canonicalize, hash and sign

<deiu> https://github.com/w3c/vc-imp-guide/issues/3

<Zakim> jonathan_holt, you wanted to comment the role of multihash

<manu> Multihash and Multibase is what hashlink uses... so, the suggestion includes jonnycrunch's notes.

<dlongley> scribenick: dlongley

DavidC: I agree that anything put on the Web can change ... but we've got a rogue issuer if they are issuing different contents with the same ID.

<oliver> resolved the conflicts

DavidC: I was responding to Manu's point that you can't just use the ID on the VC on its own. But my point is that every VC should have a unique ID. If I include a VC in another VC they should never issue two VCs with the same ID.
... A VC ID on its own should be good enough on its own.

manu: Strongly disagree. You said the issuer "should not do X" but there is nothing to guarantee that they did not do X, either a software bug, MiTM attack, injection attack, all kinds of ways that might not happen.
... If you're using a URL to represent the information, you're using a system that's susceptible to change. You can do that, but you may also want to be able to update the VC that's associated with that ID.
... I'm very concerned about us making any kind of suggestion that including a link to an external piece of data is ok -- I think we want to at least say that if you want to have certainty that things haven't changed that you use a content hash.
... If you don't, the assumption is that that data might change.

DavidC: When I issue a VC the link only has to be a URI, there's no guarantee that it even has to be published on the Web anywhere.
... To reference the VC in the way you're saying, you have to get a hold of it...
... It's who guards the guards, it's going way over the top. If I've got something that's digitally signed with a unique ID inside it that should be enough.

scribenick: manu

dlongley: What we should say in the impelmentation guide is say there are different risk profiles.
... If we want to be clear to the person consuming what was signed, you include a content hash. That way, they can check and see the content that is signed.
... If you don't include it, you're requring some other mechanism for it to not change, or you are saying that you find that the data changing is an acceptable risk.

<manu> to be clear, dlongley and I are saying the same thing.

scribenick: dlongley

DavidC: That is a more balanced approach, certainly.

<brent> +1 as long as its clear that "other mechanisms for ensuring immutability" are acceptable

<dlongley> +1 to brent

DavidC: David introduced the notion of risk in there and we should put that in there, if you trust the issuer and assume it hasn't been hacked, etc.

scribenick: manu

dlongley: This doesn't necessarily have something to do with trusting the issuer... for example, the issuer might lose their domain name... this doesn't have to do with hacking or attacking anyone. We should be clear that links to other pieces of information, even though it is not accessible over HTTP, the information could change. We should be clear to implementers that they include a content hash to make it clear to other people about what content they're signing.

scribenick: dlongley

deiu: May I suggest we leave this issue open and leave arguments in the comments?

<deiu> https://github.com/w3c/vc-imp-guide/issues/4

burn: Ok, then people do need to enter these comments into issue #4.
... Let's keep this moving offline.
... The group ends at the end of September and in the middle of Sept. people won't be paying attention because many participants will be working in the DID WG. Let's get these issues wrapped up.

<manu> oof, 1-2 weeks will be very difficult :(

<manu> good thing we can update it after the fact.

<deiu> https://github.com/w3c/vc-imp-guide/issues/3

DavidC: I wanted to publish the full details of what we're doing with our implementation... but can't. I had a chat with Dave Longley and the WebAuthn WG put a note in the spec to say that different origins could be used in the future. This is why in our implementation we've had to put a workaround in there.

<Zakim> manu, you wanted to note we demoed this at RWoT7 Canada...

DavidC: So that everyone might implement the same workaround but can't talk about the solution for business reasons.

manu: Just to be clear -- we cannot talk about IPR in this call, or even suggest anything that could be under IPR.
... So, don't talk about IPR at all, we don't want to hear about it on the call.
... The other thing I wanted to mention was a follow up on a few things off of what Dave Longley had mentioned with David. This is a feature that we actually demo'd at Rebooting the Web of Trust.

<burn> Manu is correct. Under no circumstances can you say anything about patents

manu: You can go to your digital wallet, register your two factor auth device. We demo'd the Veres Wallet stuff and you register your device and we had to use a modified version of Chrome, a 10 line change to the browser to enable this.
... The second rechartering for the WebAuthn WG is working on this and other groups are requesting this feature too. Because we registered the FIDO device we were able to create a VerifiablePresentation and use the device to sign it before sending it to the verifier.
... We agree it's super important and useful to support. It's one of the things we may be able to ask for as the DID WG and this group, to enable this stuff to be enabled through WebAuthn. Any other alternative we should do a very thorough review on because it's really hard to get the security characteristics right.
... +1 for proposing things but absolutely nothing that's IPR related.

DavidC: Understood.

deiu: Do you think it's worth actually mentioning something from the Veres Wallet in this issue or adding a PR that describes how WebAuthn works?

manu: Yeah, we don't have to be to be specific about the product, it should work with any Web-based wallet and it works with the Credential Handler API, which is also important to note. Also, absolutely no IP around it, we've established that.
... We want to get something into the implementation guide and into a WG setting where no one can come in and patent it after the fact.

deiu: I don't want to put more work on Digital Bazaar's plate but do you think someone can put in a PR for this?

manu: We shouldn't close it, we'll try very hard to get to it but no promises.

deiu: I will remove David Chadwick from assignees since he can't provide details.
... Do you have anyone specific to assign?

manu: It would be Dave Longley or myself, probably.

deiu: Ok.

<deiu> https://github.com/w3c/vc-imp-guide/pull/19

deiu: I suggest we move forward. I know Oliver has fixed the conflict in that PR. If you'd like to quickly take a look at #19.
... We need one more approval.
... Any one against merging PR #19?

<manu> +1 to merge

<DavidC> dlongley: I can take over the minutes now

<oliver> (sorry, i have to leave)

<scribe> scribenick: DavidC

<deiu> https://github.com/w3c/vc-imp-guide/issues/2

<deiu> https://github.com/w3c/vc-imp-guide/issues/1

<Zakim> manu, you wanted to wonder about other sections that are missing.

Manu: are there issues that people would like to see that convert into sections of the document

Use Cases document update

<burn> https://github.com/w3c/vc-use-cases/

<stonematt> https://github.com/w3c/vc-use-cases/pull/105

Matt: Iot use case being worked on

<manu> +1 to merging IoT use case

Matt: PR#103 needs some tweeking

<TallTed> 35 open issues?

Matt: by next week we need a clean use case documet
... not looking for new content now.

documet -> document

TallTed is concerned that there are still 35 open issues on the document

Matt responded it is a lot, but he thinks that by reviewing them, a lot will be resolved

Burn: the implementation guide and use cases are working group notes. They are not standards
... thus it does not matter how many open issues there are.

<TallTed> Issues *can* be turned into "This is an open question..." in the doc

Burn: all that is required is for the WG to say it is ready to be published
... that being said, we should of course endeavour to resolve as many open issues as possible

<burn> +1 Ted

TallTed said that all open issues should at least be addressed by saying we are not addressing this

Matt agreed with TallTed

Implementation Guide

<manu> https://w3c.github.io/vc-imp-guide/

manu: thinks that aspirational stuff should be removed
... thinks that LD proofs will use COSE and CBOR more than JWTs

<Zakim> manu, you wanted to ask isn't that the section Dave Longley just wrote?

Jonathan_holt thinks it is hard to specify COSE implementation stuff as it is binary

Manu agrees that this is the way that things seem to be going

scribenick: manu

dlongley: I think we should say: If you're using VCs, use its decentralized extension mechanism... if you're using JWTs, use JWT's centralized extension mechanism.

DavidC: When you pick a URL, should it be dereferenceable? You can use an OID, but you can't look up OIDs... but advantage is, if it's an attribute, and it equals LDAP directory, you can connect the two.

dlongley: perhaps what should happen is you should talk about how you can do that w/ VCs if you want to.
... All this wrt. "what sort of URI should I use?" is an matter of implementation/risk/etc.

DavidC: We can write some of this stuff... matter of cycles and time... when do we want to be done w/ this document.

burn: In a couple of weeks, I'd like to close the document...

<Zakim> manu, you wanted to say how we publish the document.

scribenick: dlongley

manu: When it comes to publishing the document; clearly we won't be able to get all this stuff in based on our track record. The good news is that when W3C publishes an update to an existing document they include a big warning that directs people to the new version. I suggest that when we publish, we immediately put in this document is out of date.
... But then what happens is that the document gets ignored because many of us we'll jump into the DID WG, etc. But noting all these things in the implementation guide is important. That's just a suggestion, when we publish this in the group we point to the live version and direct people over there.

burn: Any other comments or discussion on the implementation guide at this time?

manu: Question for the ZKP folks. The implementation guide doesn't mention it a lot. We may want to point people ... either directly put stuff in the spec or point to external documents, thoughts on that?

brent: I agree, we need more in the guide on ZKPs. I will formally make it my task to make sure that happens.

manu: Awesome, thank you, Brent.

scribenick: DavidC

dlongley: I can scribe again now

<burn> ACTION: Brent to add more text on ZKPs to implementation guide

Manu: we should add more text about digital wallets
... we need a section about ongoing work so that folks know we have not finished yet

kaz: is it possible to add ".jsonld" identifier to the "v1" file (and make it "v1.jsonld") on GitHub?
... because github.com site cannot handle mime type setting

Manu: we cannot change our spec now

kaz: we can continue to use "www.w3.org/2018/credentials/v1" as described by the spec
... my point is just changing the filename of "v1" to "v1.jsonld" (whose content is JSON-LD) on the GitHub side
... maybe the Webmaster knows about nicer setting and I'm asking him about that, but he is on vacation now and we need to wait for the response

Manu: can we take this offline please

burn: this has been going on for many months now. we need a call with the W3C web master please

kaz: can have a joint call with the Webmaster after he gets back from vacation
... but as I mentioned, I'm already asking the Webmaster about a nicer solution, so would see the response first

<jonathan_holt> https://github.com/jshttp/mime-db#adding-custom-media-types

<jonathan_holt> https://help.github.com/en/articles/mime-types-on-github-pages

UK Govt call for Evidence (D Chadwick) https://lists.w3.org/Archives/Public/public-vc-wg/2019Jul/0021.html

<dlongley> scribenick: dlongley

DavidC: The reason I brought this to the view of the group -- as you know I've been funded to look into VC and commercialization and I've been invited to build an MVP and during that time I've talked to various people in gov't and the post office about improving their federated system.
... They've issued a document now asking for views in people in groups, etc. on why they need to improve the identity system they use in the UK. Many of which can be answered by VCs. Rather than me writing my own response it would be much better if this group would produce an official response from the VCWG.
... And say how VCs can help achieve what they're looking for. You'll see if you look at the URL I've provided VCs address the needs.

<Zakim> manu, you wanted to urge that the group should respond officially... including all entities that are currently members of the WG.

DavidC: We talk about where we can improve trust and questions on each section, lots of good sections we can provide good input. Would you be willing to have the group provide a collective response that we can put our name to?

manu: +1

<Dudley> +1

manu: I feel very strongly that this group should respond, big stuff, thank you David for bringing it to the group's attention. Unless there are objections we should put this out to a group response and unless there are objections say we support the response as a group.
... It's kind of every single member saying VCs are important to use to solve this problem and here's why. And here's a list of orgs in the group. Would anyone say that they're not interested in attaching their name to it... in order to do that we need 1-2 weeks to collect objections, etc. and go through that process. I don't know if you, Dan or Kaz disagree with that approach, would like to make that the goal.

kaz: I'm not objecting personally, but given we've tried to respond, the whole VCWG, maybe we need to talk with the W3 communications team.
... From a process point.

manu: I think that's a good idea to involve them. I don't think Comm team has any authority over WG statements.
... Clearly we want to involve them in that we want to respond in this way. There's also a liaison that W3C has with ISO... in this case it's direct, it's David.
... I don't know what we need to do there, we should involve Comm.

<agropper> I would like to particiapte in drafting a group response.

manu: David, is there a timeframe?

<Identitywoman> +Q

DavidC: It's a public call for response, anyone can respond. We don't have to be formally invited. The date is 15th of September (I think) when they want a reply around about that date.
... Sunday Sept 15th at 11:59 BST.
... They give an email address for response, no more than 2000 words, PDF or word/open document format.

<Zakim> burn, you wanted to ask how we get to a resolution

burn: Thank you. I just wanted to say that this is a great idea, I do have a practical concern on how we get to resolution. I have the same understanding as Manu that the WG can make any statement it wants, doesn't require approval.
... Manu you're saying that everyone has to put their name to it, this isn't a document that lists everyone's names, it's some sort of email response that lists the name of the WG. We don't need names on it just not objections from the WG to put the WG name on it.

kaliya: Just a thought to help explain the "why" I figured out -- VCs find low cost infinite technical federation.

burn: Thanks.

kaz: From my viewpoint as W3C team contact for this WG -- we should talk with Comm team and then W3 management (if needed) after that.
... So talk to Jeff Jaffe quickly, etc. Talk about this with them.
... Even if we don't need "approval" here I think talking with them would be better.

<Zakim> manu, you wanted to note that we took a look at JSON-LD Context for mobile driver's license have feedback.

burn: I agree, it's always good to do that.

manu: Yeah. The other comment is that, David, we did look at the JSON-LD `@context` you sent over, it's in the right direction, needs more work, there are benefits drawbacks to the OID approach. It's really a question about what's best. What's the time frame for us to get a response back to you?

DavidC: The first meeting is tomorrow, we'll be discussing then. I don't feel strongly either way what the reference should be and they already use OIDs in their document. So it seemed to me that we could use LDAP attribute OIDs and not have our own. The other problem is that it doesn't publish things.
... We're used to putting things in URLs, they don't publish things, ISO doesn't share without payment, etc. Trying to publish things might be against the ISO spirit, whereas OIDs work, keeps it in house.

Other implementation topics

<scribe> scribenick: DavidC

Burn: any other topics?

<stonematt> bye all

Since there was no response, burn thanked everyone and reminded them to keep working on the implementation guide

[adjourned]

Summary of Action Items

[NEW] ACTION: Brent to add more text on ZKPs to implementation guide
[NEW] ACTION: Kaz/chairs to set up PR previews on https://github.com/w3c/vc-imp-guide
 

Summary of Resolutions

[End of minutes]

Minutes manually created (not a transcript), formatted by David Booth's scribe.perl version 1.154 (CVS log)
$Date: 2019/08/06 19:00:49 $