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github.com/nuts-foundation/go-did

A library to parse and generate W3C DID Documents and W3C Verifiable Credentials.

Example usage

Note on parsing: in earlier versions, DID documents, credentials and presentations were parsed using UnmarshalJSON. Now, ParseDocument(), ParseVerifiableCredential() and ParseVerifiablePresentation() should be used instead: they better support VCs and VPs in JWT format.

Parsing a DID document

didDoc, err := did.ParseDocument(didDocJson)
if err != nil {
    panic(err)
}
// do something with didDoc

Creating a DID document

Creation of a simple DID Document which is its own controller and contains an AssertionMethod.

didID, err := did.ParseDID("did:example:123")

// Empty did document:
doc := &did.Document{
    Context:            []did.URI{did.DIDContextV1URI()},
    ID:                 *didID,
}

// Add an assertionMethod
keyID, _ := did.ParseDIDURL("did:example:123#key-1")

keyPair, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
verificationMethod, err := did.NewVerificationMethod(*keyID, did.JsonWebKey2020, did.DID{}, keyPair.Public())

// This adds the method to the VerificationMethod list and stores a reference to the assertion list
doc.AddAssertionMethod(verificationMethod)

didJson, _ := json.MarshalIndent(doc, "", "  ")
fmt.Println(string(didJson))

Outputs:

{
  "assertionMethod": [
    "did:example:123#key-1"
  ],
  "@context": "https://www.w3.org/ns/did/v1",
  "controller": "did:example:123",
  "id": "did:example:123",
  "verificationMethod": [
    {
      "controller": "did:example:123",
      "id": "did:example:123#key-1",
      "publicKeyJwk": {
        "crv": "P-256",
        "kty": "EC",
        "x": "UANQ8pgvJT33JbrnwMiu1L1JCGQFOEm1ThaNAJcFrWA=",
        "y": "UWm6q5n1iXyeCJLMGDInN40bkkKr8KkoTWDqJBZQXRo="
      },
      "type": "JsonWebKey2020"
    }
  ]
}

Parsing Verifiable Credentials and Verifiable Presentations

The library supports parsing of Verifiable Credentials and Verifiable Presentations in JSON-LD, and JWT proof format. Use ParseVerifiableCredential(raw string) and ParseVerifiablePresentation(raw string).

Creating Verifiable Credentials and Verifiable Presentations

The library supports creating Verifiable Credentials and Verifiable Presentations in JWT proof format.

Use CreateJWTVerifiableCredential() and CreateJWTVerifiablePresentation().

See vc/vp_test.go and vc/vc_test.go for examples.

Supported key types

• JsonWebKey2020
• Ed25519VerificationKey2018
• EcdsaSecp256k1VerificationKey2019 (pass build tag to enable: -tags=jwx_es256k)

Installation

go get github.com/nuts-foundation/go-did

Testing

go test ./... -tags=jwx_es256k

State of the library

We keep the API stable, breaking changes will only be introduced in new major versions.