Re: [MINUTES] Data Integrity 2025-08-01 (was: Re: Advances in Longfellow ZK (was: Re: Event Updated: CCG — Data Integrity))

Hi Manu,

Thanks for your meeting summary! I’m aware of the recent issues with the last two calls…https://lists.w3.org/Archives/Public/public-credentials/2025Aug/0059.html

We really appreciate the community’s continued efforts to keep things running smoothly!

Best,

Denken
On Aug 8, 2025 at 9:40 PM +0800, Manu Sporny <msporny@digitalbazaar.com>, wrote:

> On Fri, Aug 8, 2025 at 6:38 AM Denken i <denkenie@gmail.com> wrote:
>
> > Hi folks, sorry I missed it. Will the minutes (with text and video, as usual) be published for that event?
> >
>
> Hey Denken, unfortunately we had our first failure of Google Meet to
> transcribe and record a CCG call. I've searched the archives, but it
> looks like Google Meet failed to do the recording and transcription of
> that particular meeting.
>
> This has never happened before, and it's really unfortunate that it
> happened for this very important call. I will attempt to summarize the
> meeting below:
>
> Abhi, Matteo, and Sergei presented a number of changes that would need
> to be made to make SD-JWT more efficient wrt. LongfellowZK. The group
> agreed that the change is necessary, highlighted that they do not
> believe SD-JWT is well-suited for efficient ZKPs, and noted that
> alternate mechanisms would work better.
>
> Abhi then presented a new Pedersen commitment based approach to
> LongfellowZK that is quite similar to BBS, which the group does have a
> lot of expertise in. After some light evaluation of Abhi's proposal by
> the group, we all agreed that it was a very promising direction for
> the following reasons:
>
> 1. Pedersen commitments are well known (having been published in 1992)
> and having been analyzed as a part of the BBS work at the IETF CFRG.
>
> 2. Serialization into a list of messages is also well known for the
> BBS work and the W3C Data Integrity work.
>
> 3. One of the biggest benefits is that we can now evaluate a message
> with thousands of commitments very quickly (several hundreds of
> milliseconds).
>
> 4. LongfellowZK has been introduced at IETF CFRG as a general
> cryptographic primitive and is under active review.
>
> 5. We identified that pseudonyms were missing in Abhi's proposal, but
> Abhi noted that he believes adding them in would be fairly
> straightforward.
>
> 6. The mechanism described by Abhi would be easy to integrate into a
> W3C Data Integrity cryptosuite, since most of it is already
> implemented via the BBS Data Integrity cryptosuite.
>
> 7. What would be needed would be a lightweight IETF CFRG draft that
> explains how to put together some of the BBS approaches that have
> already gone through review, but using Longfellow ZK in a some key
> places.
>
> In other words, what Abhi, Matteo, and Sergei presented seemed to fit
> into existing work on BBS, which has made it quite far within IETF
> CFRG, which means that we wouldn't have to start over from scratch for
> a new ZKP mechanism that uses LongfellowZK. It would be standardizable
> within 1-2 years vs. it being a 3-5 year endeavor. We think we had the
> right people in the room to create the solution, perform review, and
> get the specs done at IETF and W3C.
>
> We ended the call by committing to help Abhi and his team in whatever
> way we can to create a Data Integrity cryptosuite that uses
> LongfellowZK. The concrete work items that were identified were:
>
> 1. [Abhi/Greg] Creation of a lightweight spec bridging LongfellowZK to
> BBS/Pedersen primitives.
>
> 2. [Greg/Dave] Creation of a W3C Data Integrity cryptosuite that uses
> the Pedersen version of LongfellowZK.
>
> 3. [Data Integrity group] Review of specifications and approaches to
> ensure optimal mechanism is created that doesn't have to pay the price
> of having to conform to existing digital credential serializations
> that are not well suited for ZKPs.
>
> We'll keep moving this work forward in the Data Integrity group and
> Abhi and team have an open invitation to use future calls to move the
> LongfellowZK stuff forward within our community.
>
> -- manu
>
> --
> Manu Sporny - https://www.linkedin.com/in/manusporny/
> Founder/CEO - Digital Bazaar, Inc.
> https://www.digitalbazaar.com/
>