2024-05-13 AnonCreds Working Group Meeting

Summary

• Revocation Specification – https://hackmd.io/LGlyexsRSBqrm7TIKzzZ_A?view
• What's happening at the W3C VC-DI-BBS Working Group - Discussion about next steps
• Getting BBS Support in AnonCreds v2
• Reminder: New Meeting Times

Time: 7:00 Pacific / 16:00 Central Europe
Call Link: https://zoom.us/j/97954159540?pwd=WWk3WmQ3MVh1SXBYZGVreGl0QllGdz09

Recording:

Notices: 

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

Meeting Attendees

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

Related Specifications and Repositories:

• AnonCreds v1.0:
  • The v1.0 specification is published here: https://hyperledger.github.io/anoncreds-spec/
  • The Working Group uses this GitHub repository to manage the specification: https://github.com/hyperledger/anoncreds-spec
  • The AnonCreds Methods Registry: https://hyperledger.github.io/anoncreds-methods-registry
  • The v1.0 implementation in Rust is here: https://github.com/hyperledger/anoncreds-rs
  • The v1.0 implementation is dependent on this Rust CL Signatures implementation: https://github.com/hyperledger/anoncreds-clsignatures-rs
• AnonCreds v2.0
  • The initial framework for the v2.0 specification repository is here: https://github.com/hyperledger/anoncreds-spec-v2
  • The v2.0 implementation in Rust is here: https://github.com/hyperledger/anoncreds-v2-rs
  • Underlying AnonCreds v2.0 are cryptographic libraries in Hyperledger Labs Agora

Meeting Preliminaries:

• Welcome and Introductions
• Announcements:
  • Workshop Wed. April 24th: Zero Knowledge Proofs and ZK Programming in Blockchain Application Development
• Any updates to the Agenda?

Agenda

• Specification for Privacy Preserving, Scalable Revocation – https://hackmd.io/LGlyexsRSBqrm7TIKzzZ_A?view – Mike Lodder
  • How is binding done to between the credential and the revocation?
  • How are keys managed when there are multiple revocation managers (multi-party computation configuration)?
• VC-DI-BBS Specification and AnonCreds V2 – getting to collaboration?
  • BBS Signatures specification is moving through IETF – https://datatracker.ietf.org/doc/draft-irtf-cfrg-bbs-signatures/
    • Incubation happening at DIF
  • DHS has announced support for using BBS Signatures for selective disclosure and unlinkability
    • Intended approach is to use Parallel Signatures, and to sign VCs with a NIST approved signature and BBS Signatures
  • W3C Working Group has a release candidate spec – vc-di-bbs
    • Selective disclosure, unlinkability, holder binding, pseudonyms (issuer and holder defined) (directed identifiers)
    • Left off – revocation (!!), blinded secret, claim equality, set membership, range proof, signed integer
    • RDF Canonicalization is used – JSON-LD-based, and same as other VC-DI cryprosuites
• Getting BBS Support into AnonCreds v2
• Reminder of new meeting times
  • Second Monday of each month – 7:00 Pacific / 16:00 Central Europe
  • Fourth Monday of each month – 15:00 Pacific / 16:00 Mountain / Super Late Central Europe (Midnight...) / 10:00 Auckland
• Open Discussion
  • Using an accumulator as a space-efficient way to enable set membership of hashes? For example:
    • Up to a million high-entropy hashes
    • Only needed query: "is hash XYZ in the set (Y/N)?" – e.g., given hash XYZ and the accumulator, can I answer that question?

To Dos:

Action items

• Links to be referenced in the spec and used where needed:
  
  • From Will Abramson : https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.186.5994&rep=rep1&type=pdf
  • From Will Abramson : https://github.com/hyperledger/indy-hipe/blob/c761c583b1e01c1e9d3ceda2b03b35336fdc8cc1/text/anoncreds-protocol/README.md