2023-06-26 AnonCreds v2.0 Working Group Meeting

Summary

• Presentation Data Models
• Predicate Types
• Open Discussion

Recording of Call:  

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 Repositories:

• Mike Lodder's proposed Data Models: https://hackmd.io/ZlsnLoclSveePJOZljgMfA
• AnonCreds v2.0 Specification Repository: https://github.com/hyperledger/anoncreds-spec-v2/
• AnonCreds v1.0 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

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.

Meeting Preliminaries:

• Welcome and Introductions
• Announcements:
  • 2023.05.15 (this Thursday): Presentation: ZKPs – the High School Math Edition - Stephen Curran at the Identity SIG Meeting
• Updates to the Agenda?

Agenda

• Proposed Presentation Data Models, based on what Mike Lodder has presented and documented here: https://hackmd.io/ZlsnLoclSveePJOZljgMfA
• Review of Predicates
  • For each – what Schema Claim Types can/must be used? 
  • Hide signature – proof of signature (unlinkable)
  • Hide attribute - reveal or hide - Schnorr Proof
  • Set memberships, such as
    • Zip/postal Code
    • State
    • City
    • Accumulator
  • Commitment - same value
  • Range Proof
  • Verifiable Encryption
  • Commitment
  • Not discussed: Claim equality across credentials (e.g. proof that the claims in two credentials are the same without sharing the value)
• Schema Claim Type:
  • Would it make sense defining date related schema claim types that are especially useful to use in ZKP predicates?
    • "iso860_date" – encodes to dateint e.g., 2023.06.26 is 20230626
    • "iso860_datetime" - encodes to Unix Time e.g., seconds since Jan 1, 1970

Future Calls

• Collect some use case specific examples and continue the discussions:
  • Applying the data structures to a real use case or two
    • Take an existing AnonCreds Schema (maybe this) and Credential Definition (maybe this) and define what it would be using Mike's proposed data models.
      • Where would the data models exist, such as on ledger, in the AnonCreds specification?
  • What concrete uses other than link-secret is there for blinded data in a credential?

To Dos:

Action items