10F/ An Extended LDP-BBS 2020 and ZKP-LD Playground

An Extended LDP-BBS 2020 and ZKP-LD Playground

Wednesday 10F

Convener: Dan Yamamoto and Kazue Sako

Notes-taker(s): ***

Tags for the session - technology discussed/ideas considered:

BBS+, ZKP, Cryptography, JSON-LD

Discussion notes, key understandings, outstanding questions, observations, and, if appropriate to this discussion: action items, next steps: 

Session Slides: https://drive.google.com/file/d/1xKjXbzwMdZC5azPuRy-mtWuyfEuqsb8T/view?usp=sharing

Playground link: https://playground.zkp-ld.org/

Github Code links:

https://github.com/yamdan/zkp-ld-playground

https://github.com/yamdan/jsonld-signatures-bbs

https://github.com/yamdan/bbs-signatures

https://github.com/yamdan/bls12381-key-pair

The Mattr’s BBS+ LD implementations were forked and improved upon. Instead of signing each whole N-Quad, each term of each N-Quad is signed. Multiple credentials can be aggregated.

Demo of ZKP-LD playground showed multiple issued credentials with different credential subjects being aggregated into a single presentation

There is an intention to use these changes as the start for a new signature suite (perhaps BbsBlsSignature2021)

There is interest in future work: recipient binding, range proofs, ...

The id URLs can be anonymized for each presentation, but the same id’s are the same within a single presentation.

It may also be possible to use k-times anonymous presentations

Currently use an informal URN: urn:anon:xxxxxxxxxxxxxx for anonymized URIs. Standardizing it should be one of the future works.

Finding alternatives for LD Canonicalization (if any) is one of possible ways to improve efficiency.

Current version of ZKP-LD Playground and three libraries possibly contains bugs; any feedback is welcome to make them better.

Discussion of using this extension with DIF presentation exchange

Zoom Chat:

Brent Zundel:

+1 to defining a new signature suite

Brent Zundel:

exactly what I was getting at

Kyle Den Hartog:

Second follow up question

Kyle Den Hartog:

Have you considered other canonicalisation mechanisms to reduce the proof size?

Nuttawut (Finema):

May I ask if “urn:anon” a standardized URN?

Nuttawut (Finema):

thank you

David Huseby1:

So you’re going to keep a cache of ZKP presentations to try to detect people falsely presenting somebody else’s proof?

Hakan Yildiz:

Absolutely, great work!

aj-finema:

Is it possible to share the presentation?

aj-finema:

Thank you :)