jsonld-vc-bbs-go

jsonld-vc-bbs-go is a go module that can be used to implement the issuance, verification and selective disclosure of BbsBlsSignature2020 W3C JSON-LD verifiable credentials.

Table of Contents

• Description
• How to use
  • Usage example
  • Suites
    • SignatureSuite2020
    • SignatureProofSuite2020
  • Additional contexts
• Contributing

Description

In the space of Digital Identity, W3C has defined a mature standard for BBS+ signed Verifiable Credentials in the format of JSON-LD (i.e. JSON Linked-Data).

The advantage of BBS+ credentials is mainly on the privacy side:

• they natively support selective disclosure;
• they achieve unlinkability between different presentations.

Therefore, they can be used in contexts where the privacy requirement is very sensitive.

How to use

To add this module within your go project, run:

go get github.com/hyperledger-labs/jsonld-vc-bbs-go

Usage example

A usage example can be found in this main.go. You can execute it by running:

go run example/main.go

Suites

The library exposes 2 suites:

• SignatureSuite2020: suite to use to sign and verify a JSON-LD credential with a BBS+ keypair;
• SignatureProofSuite2020: suite to use to perform selective disclosure of a BBS+ JSON-LD credential.

SignatureSuite2020

The SignatureSuite2020 presents the following interface:

// Sign a JSON-LD credential
func (s *SignatureSuite2020) Sign(credential model.JsonLdCredentialNoProof) (model.JsonLdCredential, string, error)

// Verify a BBS+ JSON-LD credential
func (s *SignatureSuite2020) Verify(credential model.JsonLdCredential) *model.VerificationResult

SignatureProofSuite2020

The SignatureProofSuite2020 presents the following interface:

// Derive a selective disclosure proof from a BBS+ JSON-LD credential
func (s *SignatureProofSuite2020) DeriveProof(signedCredential model.JsonLdCredential, frameDocument model.JsonLdFrame, nonceBytes []byte) (model.JsonLdCredential, error)

// Verify a selective disclosure proof
func (s *SignatureProofSuite2020) VerifyProof(signedCredential model.JsonLdCredential) *model.VerificationResult

Additional contexts

The library comes with some preloaded JSON-LD contexts. In case your credential requires additional context to use, you can pass it as follows:

options := &model.SignatureSuiteOptions{
  Contexts: map[string]map[string]interface{}{
    "https://w3id.org/mycontext/v1": mycontextV1, // additional context
  },
}

issuerSuite := jsonldbbs.NewJsonLDBBSSignatureSuite(ipbBytes, iskBytes, options)

Contributing

Any contribution is welcome. Here a list of the next steps to achieve:

• bbs-2023 suite implementation;
• Blind issuance of the credential;
• Unblinding of blindly issued credential.