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Multi-Signature Verifiable Credentials and Conditional Proofs

Jack Tanner

https://jackandtheblockstalk.com

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CTO @ Tonomy Foundation

https://tonomy.foundation

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Agenda

  1. What we have done
  2. Why is this important
  3. Conditional Proofs W3C spec
    1. Antelope DID and other DID methods
  4. Decision to use did-jwt library
  5. did-jwt changes
    • Nested JWTs
    • New did-jwt recursive architecture
  6. Implementation characteristics
  7. What’s next

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What we have done

Implemented support of W3C CCG Conditional Proof standard

into the DIF did-jwt, did-jwt-vc and did-resolver libraries

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Supports smart signatures

  • Multisignature (1 of N, M of N, M of weighted N)
  • Delegated signatures
  • Relationships
  • Combinations of the above

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Why is this important

DIDComm / Verifiable Credentials now support

  • Multisignature (1 of N, M of N, M of weighted N)
  • Delegated signatures
  • Relationships
  • Combinations of the above

What can this be used for?

  • MFA
  • Multi-device support
  • Multi-party signatures
    • multiple people approve a document
    • Multiple people approve a new board member based on their shares/assets
  • Delegated authorizations
    • A person in a company/DAO authorizes a document on behalf of the company
    • People authorize a document on behalf of several companies

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  • did:webs (did:web + did:keri)

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Conditional Proofs W3C spec

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https://github.com/w3c-ccg/verifiable-conditions is a DID Document Verification Method Type

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Decision to use did-jwt library

https://github.com/Tonomy-Foundation/Antelope-SSI-Toolkit/issues/17#issuecomment-1263319391

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Nested JWTs

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did-jwt architecture change

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Implementation characteristics

  • using did-jwt
  • DID, VC and JWT standard compliant
  • Can be used for JSON-LD proofs as well with the JWS proof
  • Smart Signatures (https://youtu.be/E9sbWKbfyJU?t=452)
    • Composable using recursive conditions (part of the standard)
    • Inspectable
    • Provable
    • Deterministic
    • Bounded by limiting recursion or time bounding
    • Efficient?

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What’s next

Conditional proof

  • Current Implementations:
    • DIDs:
    • did-jwt
      • Vercel library
  • Further adoption:
    • JSON-LD libraries
    • more DID methods

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