JWTClaimsSet.Builder() and JSONObject - Object inside Verifiable Presentation JWT

Question

I've to create a JWTClaim which has inside a property with a JSON:

exampleClaimJson = {
     "nonce":"13234-3234345-34454",
}

In Java I'm building it like this:

JSONObject exampleClaimJson = new JSONObject();
didJson.put("nonce","13234-3234345-34454");

JWTClaimsSet claimsSet = new JWTClaimsSet.Builder()
    .subject(did)
    .claim("exampleJson", exampleClaimJson)
    .build()

But then inside the JWT the "exampleJson" claim is represented like this:

{
     ...
     "exampleJson": {
          "map": {
                  "nonce":"13234-3234345-34454"
          }
     }
}

On the other hand if I use

.claim("exampleJson", exampleClaimJson.toString())

Then it turns into:

{
     ...
     "exampleJson": "{\"nonce\":\"13234-3234345-34454\"}"
}

To me none of those look ok, in particular because the structure of the Claim will be verified and must be just a JSON, not with map declarations and not a simple string.

Does anyone know if this is the correct approach in Java? I'm looking at this Building JSON Web Token using JSONObject and JSONArray (from 2015 though..) - what's the difference between the minidev and the java json objects? Is it a normal practice to include different JSON libraries for Java projects?

Answer 1

Your code looks right - perhaps there is some kind of library incompatibility? To work with object claims, see the nimbus tests. Here is some working code:

var verifiablePresentationJson = new JSONObject()
verifiablePresentationJson.put("nonce", "13234-3234345-34454")

val did = "did:example:user123"
val claimsSet = new JWTClaimsSet.Builder()
    .subject(did)
    .claim("verifiablePresentationJson", verifiablePresentationJson)
    .build()
System.out.println(claimsSet.toString())

Note that you should be using the following class and not some other implementation:

net.minidev.json.JSONObject

Do so by adding this dependency, in the same way as the nimbus project does:

implementation("net.minidev:json-smart:2.5.0")