2023-02-20 AnonCreds v2.0 Working Group Meeting

Summary

Getting Organized
Goals of the Working Group
What are we starting with?
Open Discussion

Recording of Call:

Notices:

This specification creating group operates under the Linux Foundation Community Specification License v1.0.

	Hyperledger is committed to creating a safe and welcoming community for all. For more information please visit the Hyperledger Code of Conduct.

	Hyperledger is committed to creating a safe and welcoming community for all. For more information please visit the Hyperledger Code of Conduct.

Meeting Attendees

@Stephen Curran (BC Gov / Cloud Compass Computing Inc.) <swcurran@cloudcompass.ca>

@Rodolfo Miranda (RootsID)<rodolfo.miranda@rootsid.com>

@Mike Lodder <redmike7@gmail.com>

@Alex Andrei (RootsID)<alex.andrei@rootsid.com>

@belsy yuen (Nymlab)<belsy@nymlab.it>

Related Repositories:

AnonCreds Specification: https://hyperledger.github.io/anoncreds-spec/
AnonCreds Methods Registry: https://hyperledger.github.io/anoncreds-methods-registry
AnonCreds Rust Open Source Code: https://github.com/hyperledger/anoncreds-rs
- Ledger Agnostic AnonCreds Project Page: https://github.com/orgs/hyperledger/projects/16

Meeting Preliminaries:

Welcome and Introductions
Announcements:
Updates to the Agenda

Agenda

Presentation/Agenda Slides
Getting Organized
- Bi-Weekly meetings on Mondays at 10:00 Pacific / 19:00 Central Europe starting Feb. 20, next meeting March 6
Goals of the Working Group:
- The goal of AnonCreds v2.0 is to retain and extend the privacy-preserving features of AnonCreds v1.0, while improving capabilities, performance, extensibility, and security.
What are we starting with?
- Mike's proposal from the AnonCreds Specification Working Group Meeting of 2022.11.28
  - Extends the definition of "Schema" to include a type of each claim based on how it can be used in a presentation
    - Extends the current AnonCreds (implicit) types of Integer, Hash and Scalar (blinded) to include:
      - Scalar defined by the issuer (not just the hidden blinded link secret)
      - Enumerated
      - Range (including negative)
      - Verified encrypted
    - Enables ZKPs on additional types of data, beyond the V1.0 predicates.
  - Covers issuer signing, presentation generation and verification.
  - Requires the same interactions as in the AnonCreds v1.0 specification
  - Enables the use of more signature schemes
    - Mike proposes we could choose to support:
      - CL Signatures
      - BBS+ Signatures
      - BLS Signatures
      - Pointcheval-Sanders (PS) - https://eprint.iacr.org/2015/525
    - We agree there is a benefit to be opinionated on what to use, but will ideally make it easy to swap out what we choose to use.
- Other things to consider:
  - What data model to use – e.g. can we support the W3C Verifiable Credentials Data Model Standard?
    - Approach could be similar to what we have proposed for AnonCreds v1.0 – e.g. using JSON-LD, but don't sign the RDF tuples – sign the encoded data values as per AnonCreds.
  - What presentation request data model to use?
    - Stick with AnonCreds or switch to Presentation Exchange?
  - Revocation
- What will the V2.0 Spec contain?
  - Much like the V1.0 spec, with pointers to the cryptography to be used that is documented elsewhere.
Next Steps:
- Mike is creating a HackMD document to cover the Data Models he is proposing: https://hackmd.io/@n3EfHQ0HR9-Gab_iWRQZUA/B1b0h1MjI
Volunteers: We need additional people to lead this group. Step up, folks!