- From: CCG Minutes Bot <minutes@w3c-ccg.org>
- Date: Wed, 05 Apr 2023 17:51:38 +0000
Thanks to Our Robot Overlords for scribing this week!
The transcript for the call is now available here:
https://w3c-ccg.github.io/meetings/2023-04-04/
Full text of the discussion follows for W3C archival purposes.
Audio of the meeting is available at the following location:
https://w3c-ccg.github.io/meetings/2023-04-04/audio.ogg
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W3C CCG Weekly Teleconference Transcript for 2023-04-04
Agenda:
https://www.w3.org/Search/Mail/Public/advanced_search?hdr-1-name=subject&hdr-1-query=%5BAGENDA&period_month=Apr&period_year=2023&index-grp=Public__FULL&index-type=t&type-index=public-credentials&resultsperpage=20&sortby=date
Topics:
1. Introductions and Reintroductions
2. Announcements and Reminders
3. Data Integrity-based Selective Disclosure and Predicate
Proofs
Organizer:
Mike Prorock, Kimberly Linson, Harrison Tang
Scribe:
Our Robot Overlords
Present:
Bob Wyman, Harrison Tang, Christopher Allen, Kazue Sako, Yuji
Suga, Greg Bernstein, Lucy Yang, Paul Dietrich GS1, Stuart
Freeman, Brenda, James Chartrand, Dan Yamamoto, Gregory Natran,
Shigeya Suzuki, Erica Connell, Nis Jespersen , TallTed // Ted
Thibodeau (he/him) (OpenLinkSw.com), paulm, Kaliya Young, Jeff O
- HumanOS, Manu Sporny, Kimberly Linson, John Kuo, Kerri Lemoie,
Joe Andrieu, Dmitri Zagidulin, Dave Longley, Wendy Seltzer,
Markus Sabadello, Keith Kowal, Sandy Aggarwal, Brian Campbell,
Phil L (P1), Marty Reed, Nate Otto, Will, Stephen Curran, David
I. Lehn, Leo, Jennie Meier, Geun-Hyung, bengo
<christopher_allen> Good day everyone!
Our Robot Overlords are scribing.
<christopher_allen> has any voice started? All is quiet.
Harrison_Tang: So hello everyone welcome to this week's w3c ccg
meeting so today our main topic we actually invited Dan Yamamoto
Causeway Socko uh yeah Suzuki and ug Suga to come here and
present the link database verifiable credential with selected
disclosures on the accessibility.
Harrison_Tang: e and predicate proof so.
<shigeya_suzuki> (Note: I'm not part of authors.)
Harrison_Tang: Before we get to this man agenda just want to do
some admins first but want to thank them in advance for jumping
out here because it's actually one am Japan time so so this is
definitely quite an honor for them to actually join us as w3c she
G here today.
<kimberly_wilson_linson> Christopher - you might need to reboot.
We have audio
Harrison_Tang: Right so quick agenda just want to do some quick
reminders for the code of ethics and professional conduct
reminder and yeah they know I think we've been doing very well
just make sure that we remain respectful to one another never
seen he did you know kind of disrespectful arguments in this
channel before but just want to do a quick reminder again all
right IP note anyone can participate in these calls however.
Harrison_Tang: overall substantive contributions.
Harrison_Tang: Gigi walk items must be members of the ccg with
for IP our agreement sign so you have any questions about that
just reach out to any of the cultures.
Harrison_Tang: All right these calls are recorded and it's
automatically transcribed and we try to publish the transcription
within a couple days.
<kazue> present +
Harrison_Tang: Use the Gchat to Q speakers so you can type in Q
Plus to add yourself to the queue or q- to remove it and you can
do Q question mark to see who is in the cube all right let's get
to the introductions and reintroductions anyone who is new to the
all right Greg.
Topic: Introductions and Reintroductions
Greg Bernstein: https://www.grotto-networking.com/BBSDemo/
Greg Bernstein: Hi I've been hanging out on the channel for a
while but most of my work has been on some of the signatures
stuff and in particular I've been working on with the dif and the
ietf folks on BBS signatures so particularly interested in this
call and I do have some demos that you can try if you want to get
more into BBS signatures which offer selective disclosure and so
that's why I'm particularly.
Greg Bernstein: Interested in this call so if.
Greg Bernstein: Since about BBS or in particular I have a
JavaScript implementation that's up on npm give you just ask me a
question but real interested in this glad to be having this topic
presented thanks a bunch.
Harrison_Tang: Thank you Greg and then I probably would like to
follow up with you later maybe this week to see if we could
schedule a session on PBS in the church later this year yeah.
Harrison_Tang: All right then do you mind kind of introduce
yourself a little bit since you're the main main speaker today
yeah.
Harrison_Tang: Thank you thank you Dan and Kazooie do you mind
actually introduce yourself a little bit thank you.
Harrison_Tang: No thank you thank you.
Harrison_Tang: Is the honor for you guys to join us and sorry to
call on us UK I do you mind and hopefully I pronounced your name
correctly but do you mind actually unmute and introduce yourself
a little bit.
Harrison_Tang: Thank you thank you I mean it's 1 a.m. in Japan so
I totally understand and lastly you g do you mind actually I'm
you and introducers introduce yourself a little bit.
Harrison_Tang: I think you are me.
Harrison_Tang: All right I think you know I'm sorry that I just
call on people time but baby weight any other introductions and
reintroductions.
Harrison_Tang: All right that next we have announcements and.
Harrison_Tang: Any announcements and reminders.
Topic: Announcements and Reminders
Kaliya Young: https://internetidentityworkshop.com/
Kaliya Young: https://diceurope.org/
Kaliya Young: Just quickly internet identity Workshop is coming
up in two weeks if you have not registered please do so because
we are likely to sell out and then more importantly I'm working
with folks in Zurich to bring an unconference with the same
format that we use at iwt Europe the digital identity
unconference Europe dice happening.
Kaliya Young: In June.
Kaliya Young: And Zurich so if you are based in Europe please
consider joining us there and if you work with people who are in
Europe please encourage them to consider joining us there.
Harrison_Tang: Thank you Clea.
Christopher Allen: Yes if you hadn't heard it yet the next
rebooting web of trust is September 18 through 20 s in Cologne
Germany this is where we work on papers and projects and work
together to ship them before the end of the event or at least the
first draft and we're also having a publication day on April 13th
as.
Christopher Allen: A virtual.
Christopher Allen: For the six hopefully seven papers that have
gone final since the the last one so if you're interested in
participating in that look at the go-to web of Trust on info
that's all.
Harrison_Tang: Thank you thanks Christopher I'm on you you have
the floor.
<manu_sporny> VC JSON Schemas:
https://github.com/w3c-ccg/vc-json-schemas/
Manu Sporny: Thanks Harrison two things the first one is that
the VC Jason schemas work that has been incubated in the ccg has
been adopted by the verifiable credentials working group I will
put a link to that in here you see JSON schemas in this is a
request to the ccg chairs to you know make a call for support.
Manu Sporny: To move that into the new group really what.
Manu Sporny: Look we're looking for objections to move that work
into the VC WG since they already accepted it as a work item up
to the chairs on when to schedule that the second item is that at
ietf 116 I was able to present some of the work that we've been
doing in this group for the last couple of years on Multi formats
so you know if you used.
Manu Sporny: Did key if you use.
Manu Sporny: https://www.ietf.org/mailman/listinfo/multiformats
Manu Sporny: Was there multi-format show up in those things and
the ITF has given us a space to standardize that work potentially
as a mini working group or the independent submissions track if
you're interested in following this work I will put a link to the
email mailing list in here there will be discussion starting this
week on that mailing mailing list about.
Manu Sporny: Whether we should do a mini working group at ittf.
Manu Sporny: Just take it independent standards track so please
join if you would like to help move multi formats forward that's
it.
Harrison_Tang: Thank you mommy you.
Harrison_Tang: Any other announcements and reminders.
Harrison_Tang: Okay what about updates on the work items.
Harrison_Tang: All right so let's get you the man agenda again
we're very very honor to have Dan Causeway she Gaya and Yugi to
present on the topic of linked database verifiable credentials
with selected disclosures I'm going to ability and predicate
proves actually just want to give a quick shout-out to
Christopher to actually I was chatting with Christopher about
our.
Harrison_Tang: and calendar and then he is the one who actually.
Topic: Data Integrity-based Selective Disclosure and Predicate Proofs
Harrison_Tang: Reduce Dan Causeway and others to to us so a quick
shout out to him and as we know selected disclosure unlinked
ability part of the predicate proves and these kind of concepts
are important topics in our community so very very happy to have
Dan and others actually take the time to stay out until like 1:00
2:00 a.m. Japan time to give this talk so let's give them the.
Harrison_Tang: a quick shout-out virtual clap clap Santa.
Harrison_Tang: And I think the floors yours then.
Harrison_Tang: Oh yes honey do you have any comments.
Manu Sporny: Yeah it totally fine go ahead Dan.
<dan_yamamoto> Slides:
https://speakerdeck.com/yamdan/linked-data-based-verifiable-credentials-with-selective-disclosure-unlinkability-and-predicate-proofs
<christopher_allen> (the limitation of positive integer proofs is
part of what makes bulletproofs so fast)
<christopher_allen> (The limit is just slightly less than 2^32,
so a pretty large integer range, it can do lots of things, gt;
lt, inside-range; outside-range, etc.)
<greg_bernstein> Note that holder does not need secret key!
<manu_sporny> ^ thank you for that Christopher, super helpful...
didn't know it could do inside/outside
<christopher_allen> @manu it can also do other things like
averages, means, etc. with multiple sources.
<manu_sporny> @Greg, could you elaborate more on "holder doesn't
need secret key" -- you mean that the only thing you need to do a
reveal is the original BBS signed document itself, right?
<christopher_allen> @manu "Is the average of these 300 VCs >80%"
<greg_bernstein> The holder produces a proof from signature,
issuers public key, and revealed messages. No secret key (either
holders or issuers).
<christopher_allen> There are other zk-proofs that don't have
this limitation, but are 10x-100x slower.
<markus_sabadello> Current work in W3C RDF Canonicalization and
Hash WG: https://github.com/w3c/rdf-canon,
https://www.w3.org/groups/wg/rch
<kazue_sako> Bullet proofs can be combined to prove arbitrary
range, a<x<b
<manu_sporny> ^ @Christopher, averages are super important for
variations of "K-anonymity"
<christopher_allen> ^ @manu, precisely! I think in Taiwan they
say that health data is considered anonymous (legally) if it is
in groups of at least 300.
<manu_sporny> @Greg -- important to know that -- that is, "theft
of ZKP VC can result in impersonation" -- which can be
counteracted (to some degree) with a binding to a private key
(presuming private key isn't stolen as well).
<kazue_sako> Gregg, I think you meant that holder does not need
secret key of the issuer! Indeed.
<greg_bernstein> Yes
<greg_bernstein> Theft, impersonation, are problems...
<kazue_sako> So Holder has his own secret key to prove that he is
'correct', that is a binding VC.
<manu_sporny> @Kazue yes, that's what I understood as well. also,
hi! Long time no see! Thank you for saving me the last time I was
in Japan! :)
<christopher_allen> ^ @manu I'm also looking into how these
sd/anti-correlation techniques can also be integrated into
did:docs.
<kazue_sako> Dan and my students are working on those binding VC.
<manu_sporny> @Kazue good to know -- very important from a use
case perspective... the re-mapping stuff that DanY is covering
right now is vitally important as well.
<kazue_sako> My student is working on using CHAPI and issue
binding VC using blind signatures!
<manu_sporny> ^ oh, very interesting! Let us know how we can
help!
<greg_bernstein> Very interesting Kazue!
<manu_sporny> One of the harder problems is the presentation
request language... how does a Verifier ask for the ZKP fragments
that Dan is mentioning.
<greg_bernstein> I started some work with updated VC data model
v2 at https://github.com/Wind4Greg/BBS-LinkedData
<kazue_sako> @Manu, indeed. We were trying to copy 'presentation
request language' from somewhere...
<sandy_aggarwal> Dan & Kazue - I work for Mizuho Bank and would
be glad to connect with your team to discuss this project. Are
you collaborating with any banks in Japan?
<manu_sporny> Super cool! Didn't know about
https://playground.zkp-ld.org/ !!!
Harrison_Tang: Double a bobby pin do you mind taking a question
from Christopher.
Christopher Allen: I can wait.
Harrison_Tang: Yeah please please stand up.
<kazue_sako> Did OpenID Foundation had some work on presentation
request language..?
<manu_sporny> It looks like the presentation request language
you're using is JSON-LD Framing (in the Playground)
<manu_sporny> While OpenID Foundation was working on presentation
exchange, looks like you're using the existing JSON-LD Framing
specifications for that (which is good, given it's already a
standard).
<kazue_sako> We briefly looked at this for future updates:
https://danielfett.de/download/oidc-advanced-syntax-for-claims.pdf
Harrison_Tang: Thank you Dan.
Harrison_Tang: Alright I'll moderate don't worry about it so sir
yeah please.
<bengo> 👏🏻 this is rad
Christopher Allen: Wait yeah thank you Dan very much in team for
coming today I've been pushing for a long time that we have to be
a lot more serious about selective disclosure I mean I think we
have now a range of of different approaches to selective
disclosure ranging from you know hash-based disclosure of a list
in SD jot hash-based disclose.
Christopher Allen: Giroux for Jason Aldean.
Christopher Allen: Um we have the ability to do it with trees
with gordian envelope and all three of these do not have some of
the unlink ability capabilities that this is and then at you know
at the other end of the spectrum are not only these kinds of
selective disclosure but also their ways to bind this to things
like d ID documents and such so I really am am pushing that you.
Christopher Allen: No we explore these more.
Christopher Allen: And that we begin to get to the point where
we can mandate not just you know say oh this is an optional sweep
at mandate that you know our future constructions must have some
form of selective disclosure even if it's just a simple one
because I think anything less than that is a real real you know
human rights and privacy issue as you see with this example with
with vaccine credentials and other Healthcare data and.
Christopher Allen: Man who mentioned that you know the ability
to aggregate data.
Christopher Allen: It is really important for health but it's
also really risky for for privacy so I'm hoping we'll have more
discussion about these types of things and you know I'm hoping
that the ccg can you know dive into some of these specifics in
the future and really move toward you know saying this is the
minimum requirement that we have some form of.
Christopher Allen: Disclosure that's it.
Harrison_Tang: Thank you if Mill you're next.
Phil_L_(P1): Yes I didn't hear what you didn't hear your voice
can you hear.
Phil_L_(P1): Okay well thank you very much I have a really
perhaps naive question but I'm wondering what prevents the second
credential with the particular information about the vaccine from
being something borrowed from a third party and not really the
individuals and I'm wondering if the end quad term Wise
Construction that you've described is what is preventing that
sort of connection of a second.
Phil_L_(P1): Rachel to the first.
Phil_L_(P1): The second credentials.
Phil_L_(P1): Like from a third party.
Phil_L_(P1): That is not.
Phil_L_(P1): Individual of the first credential if that makes
sense.
<christopher_allen> The combination of binding the 2nd VC to the
1st is unique per presentation, so it can't be correlated.
<christopher_allen> ^ @Dan I'm trying to collect more scenarios
for SD/non-corellation use cases.
Phil_L_(P1): I understand the selective disclosure part and the
end of the hiding of particular pieces of it I think you were
saying that the that the proof method also proves that the
credential subject in the first credential is the credential
subject in the second credential is that right.
Phil_L_(P1): The other words if I if I'm the person and X2 and
your person your as a separate person that has this vaccine what
prevents me from using that the the vaccine that you got as as my
claim that I have gotten it when and I'm not selectively
preventing disclosure of these other pieces of information I
still want to make sure that it's that that original person is
the.
Phil_L_(P1): one who got the vaccine.
Phil_L_(P1): Is now being linked to.
<kazue_sako> This scenario is about one VC for Alice and the
other one is for 'vaccine'.
<kazue_sako> ZKP can take care that the same person is tied to
two VCx.
Phil_L_(P1): Thank you thank you.
Manu Sporny: Yeah two things I just wanted to say thank you to
Dan in Yugi and Kazooie for working on this stuff it's really
fantastic work so thank you you know for for pushing this stuff
forward for those of you in the community that are not aware the
BBS signature stuff is expected to go into last call at ietf over
the summer that's basically where.
Manu Sporny: We're effectively saying.
Manu Sporny: We're done with the base construction at the
cryptographic layer in as many of you know the verifiable
credentials working group has adopted the BBS crypto sweet that
bills on top of that that uses this mechanism that that day and
just presented today or subsets the mechanism that Dan presented
today so I just wanted to make it clear to everyone in the group
that this is a very real thing that is going to be that is.
Manu Sporny: Is already on standards tracks at ietf.
<christopher_allen> ^ @Dan @Kazue I'd be interested in discussing
opportunities for binding to keys in did:docs.
Manu Sporny: W3c and we expect it to be you know a standardized
probably early next year to mid next year at some point so that's
that's great so that's the first item the second item goes to
fill your question in what was said in the chat as well as Dan's
response to that is that in the base construction BBS is is is so
good.
Manu Sporny: Good at providing kind of Sudan.
Manu Sporny: Then Amity that if you were to steal that
credential you could impersonate the the individual in so there
are other things that are required to kind of rebind that in ways
that don't make it very easy to steal the credential and
impersonate so as Dan was mentioning there's this holder binding
stuff that's being talked about there's tying to a cryptographic
key that's an addition there and of course when you start.
Manu Sporny: At doing things.
<greg_bernstein> There is also a notion of "required reveal
statements"
<christopher_allen> ^ @manu I suspect there may also be some
capability to salting type approaches if you have any key
material of the verifier.
Manu Sporny: You start losing some of the anonymity aspects and
so the you know the quest is to find the right balance for the
use case there are a lot of there are a lot more considerations
that you have to take into account when you're trying to provide
this kind of unlink ability and selective disclosure that you
never had to think about when you're doing the kind of the
standard digital signatures that we've been doing for.
Manu Sporny: You know many.
<christopher_allen> …So when you get the request from the
Verifier, what you give them will be unique to them, and can't be
reused.
<phil_l_(p1)> Thanks Manu for that clarification
Manu Sporny: So that's just something to keep in mind that there
is no when you get into this kind of space there is no one right
answer you effectively have this toolbox of cryptographic
Primitives that you can put together in certain ways and they
tend to be very specific to the type of use case that you're
trying to achieve but the good news here is that fundamentally
the basis these cryptographic toolkit things are going to have
Global standards behind them.
Manu Sporny: In the next two years which means that then we can
start deploying them.
Manu Sporny: In real-world production use cases that's it.
Harrison_Tang: Thank you Manya.
Harrison_Tang: Any other questions.
Harrison_Tang: And you want to make some concluding comments.
<christopher_allen> @Dan your fluency is great!
<kerri_lemoie> That was excellent. Thank you!
Harrison_Tang: No no thank you I think your English is perfect so
thank you for taking the time and thanks again then Kazooie she
Gaya ugj for actually coming here they and I didn't fly almost 2
a.m. in Japan some thank you thank you for coming here at w3c
shiji today.
Harrison_Tang: All right so this concludes this week's at w3c
shiji meeting if you want to see what's coming just go to the
content calendar that I sent out every week right have a good one
thank you bye.
Received on Wednesday, 5 April 2023 17:51:38 UTC