2023-11-20 AnonCreds Working Group Meeting

Summary

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 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

Meeting Preliminaries:

• Welcome and Introductions
• Announcements:
• Any updates to the Agenda?

Agenda

Open Issues

• AnonCreds Spec PRs to Review
• CL Signature PRs to review
• Design and planning – AnonCreds v1.0 in the W3C Verifiable Credentials Data Model Standard format
  • The BC Gov Code With Us on AnonCreds Rust – https://marketplace.digital.gov.bc.ca/opportunities/code-with-us/d81f1bb4-4abb-4a4c-8b19-92904e0bd6a6
  • Design PR: https://github.com/hyperledger/anoncreds-rs/pull/266
  • Downstream Code With Us opportunities for Aries Cloud Agent Python and Aries Framework JavaScript
• Open discussion

Future Calls

To Dos:

• Issue to talking about what AnonCreds verifies and what is left to the issuer to verify.
• Revocation Interval
  • Approach to determine if the holder used an acceptable RevRegistry – see this Issue comment
  • Who calls the AnonCreds method to get the Revocation Registry from the ledger for verification
    • Verifier or AnonCreds?
  • To set "validation" to true/false based on the RevRegEntry timestamp in relation to the revocation interval?  Presentation 
  • Key points:
    • 1. an RevRegEntry is “current” from the time it is written, to the time of the next RevRegEntry
    • 2. “within the interval” is based on when a RevRegEntry is “current” (see 1.), not its timestamp.
    • 3. AnonCreds or the Verifier (calling AnonCreds) should calculate “within interval” (using 2.) and mark verification true if the RevRegEntry used by the Prover is within the interval, else false.
      • Dangers:
        • False-Negatives: If a strict "timestamp used is between from, to" and not based on when a RevReg is "current" (per 2.), we will get "not verified" incorrectly.
        • False-Positives: If we don't do any checking of the timestamp and the interval, the holder could incorrectly use an old RevRegEntry.
    • 4. General point: AnonCreds should return both a summary (true/false) and if false, additional data about why it was false.
  • Decision – add an optional `at_from_ts` set of entries, one per NRP, that AnonCreds can use for determining if the holder_ts is within the Presentation Request interval.

Action items

• Adding support for W3C Format AnonCreds to the anoncreds implementation and the spec.
• 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