Summary

Call Link: https://zoom.us/j/97954159540?pwd=WWk3WmQ3MVh1SXBYZGVreGl0QllGdz09

Recording: 

• https://youtu.be/sUcstipdEm8
• 2023 06 19 Hyperledger AnonCreds Specification Working Group Chat.txt
• 2023 06 19 Hyperledger AnonCreds Specification Working Group.transcript.txt

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
  • Ledger Agnostic AnonCreds Project Page: https://github.com/orgs/hyperledger/projects/16

Meeting Preliminaries:

• Welcome and Introductions
• Announcements
  
  • AnonCreds 0.1.0 Rust Implementation officially released!
  • Welcome Aritra Bhaduri a Hyperledger Mentor working on the AnonCreds Specification
    • Documenting the cryptography and aligning it with the implementation.
  • Update on the AnonCreds V2.0 Working Group
    • Last Week: How the model supports multiple underlying cryptographic signatures
    • Next Week: Presentation Data Models
• Any updates to the Agenda?

Agenda

Open Issue

• NEW ZOOM LINK!!!
• Celebration!! AnonCreds 0.1.0 Release finalized!
• AnonCreds Workshop Report
• Mentorship Update
• Deferred: AnonCreds Specification: To Do List
• Deferred: AnonCreds Specification: Mixing overview/flow information with cryptographic details
• Presentation: AnonCreds Revocation Options
  • AnonCreds v1.0 — CKS Signature with tails file
  • ALLOSAUR — Revocation Managers contacted at presentation time
  • LVVC — Linked Validity Verifiable Credential -- Revocation Manager issues a VC about the revocation state of a credential.
  • zk-SAM — Signed Accumulator Membership - publication of full revocation state
• Open Discussion

Future Calls

To Dos:

• Issue to talking about what AnonCreds verifies and what is left to the issuer to verify.
• Issue #137 added regarding further investigation into what happens to the issuance data flow nonce(s) by Belsy – definition completed, to be added to the spec. Stephen Curran 
• Issue #140 should WQL be allowed in a Presentation Request?
  • WQL is supported currently in the Indy SDK, but not in the Aries Frameworks
  • Should it be in the specification?
  • If so, in what form. From Sam Curren — don't call it WQL if we do include it – just describe it.
  • Not used and it is not clear there is a good reason to support it.
  • Complicates the specification and the implementation.
  • Decision:
    • Not supported in the specification – let's keep it out in this version
• 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