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2023-05-22 AnonCreds Specification Working Group Meeting

2023-05-22 AnonCreds Specification Working Group Meeting

May 22, 2023

Summary

  • Presentation from IBM Zurich Research Group – Revocation Scheme

  • Checkin: anoncreds-rs implementation progress, requests

  • Open Discussion

Call Link: https://us02web.zoom.us/j/85188125213?pwd=UHRUVlgweFJ0T0g4SVdDUytYSkxJUT09

Recording of Full Call:  

Recording of VB Revocation Scheme Presentation:

Notices: 

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Hyperledger is committed to creating a safe and welcoming

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Meeting Attendees

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

@Michel Sahli (Deactivated) (Adnovum) <michel.sahli@adnovum.ch>

@Rodolfo Miranda (RootsID)<rodolfo.miranda@rootsid.com>

 

Related Repositories:

Meeting Preliminaries:

  • Welcome and Introductions

  • Announcements

    • AnonCreds Workshop – May 31, 2023, 8:00 Pacific / 17:00 Central Europe

    • Currently reviewing applications for a Hyperledger Mentorship to work on AnonCreds – the specification and implementation

  • Any updates to the Agenda?

Agenda

Open Issue

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.

  • Backwards Compatibility

    • PRs in (#82, #105) that seem to change public data structures – ones that are handled outside of AnonCreds and/or by two or more participants (issuer, holder, verifier)

    • We want to retain compatibility with existing data – credentials that have been issued and the published AnonCreds objects on which they rely.

    • That extends to business logic – e.g. the handling of the objects not just by AnonCreds, AnonCreds Methods and Aries Frameworks, but also by business applications built on Aries.

    • Suggestion:

      • Include in the specification a statement about backward compatibility

        • Perhaps this is what Ankur had planned to do?

      • Formalize what data structures will be expected by AnonCreds

        • This is being done throughout the specification and verified against the current implementation.

      • As needed support sending and receiving data in "old" and "new" formats, but (for now) always sending "old" formats.

        • TBD if there are any such cases.

Action items