2023-12-18 AnonCreds Working Group Meeting

Summary

• Eliminating the need for an AnonCreds JSON-LD @context 
• Aries Issue Credential and Present Proof attachment formats
• Open Discussion

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

• Eliminating having a special `@context` for AnonCreds
  • Issue: https://github.com/hyperledger/anoncreds-spec/issues/192
  • HackMD: https://hackmd.io/@BYJVN-mpSCe5H3eaIw7-7g/ryk4dvIIp
  • Presentation
  • Discuss the updates needed to implement the changes
  • Idea: Having a commit-time "config" setting for 1.0 vs. 2.0 (or can we do better?)
• Aries Issue Credential / Present Proof Attachments
  • Current: Indy, JSON-LD - which do we use, or should we define another that (also) handles JWTs?
  • HackMD: https://hackmd.io/JEIOxf_ETnaX33kTIu7YJw?view
• 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

W3C AnonCreds + AFJ Demo

• Aries Framework JavaScript repo: https://github.com/DSRCorporation/aries-framework-javascript/tree/w3c-demo-poc
• Anoncreds-RS library, Anoncreds-NodeJs, and Anoncreds-Shared are built from the branch: https://github.com/DSRCorporation/anoncreds-rs/tree/anoncreds-wc3-wrappers
  • Use main implementation (not included, dropping of mapping  and encoding  changes)
• Update AFJ @hyperledger/anoncreds-nodejs  and `@hyperledger/anoncreds-shared` dependencies to use locally built packages