Decoded credential always wants a hasher function for sd-jwt

[cre8]

• I'm submitting a ...
  [x] bug report
  [ ] feature request
  [ ] question about the decisions made in the repository
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• Summary
  According to the note here you need to decode the sd-jwt in case the hasher function is async (which is in my canse since its executed in the browser via webcrypto). So I am decoding the list of credentials like this:

const vcs: SdJwtDecodedVerifiableCredential[] = [];
      for (const credential of credentials) {
        const decoded = await CredentialMapper.decodeSdJwtVcAsync(
          credential.value,
          getHasher()
        );
        vcs.push(decoded);
      }      
      const pex = new PresentationExchange({        
        allVerifiableCredentials: vcs,
      });

But then I am running in this error Hasher must be provided when creating a presentation with an SD-JWT VC. After logging the credentials and the conditions I get this:

{"compactSdJwtVc":"eyJ0eXAiOiJ2YytzZC1qd3QiLCJhbGciOiJFZERTQSJ9.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.wmwlrsfXYa-B15yPRTjCulWNBeWLHxIjVynKN0UgIBatzGcmloWENCVBSLPYt1xc-o0ueYyemKDa8icOaPPu1w~WyJhZmE3Mzg2OTMzOTJlOTE3IiwicHJlbmFtZSIsIk1pcmtvIl0~WyI1NzcxYjhiMDA5YzMxMzMzIiwic3VybmFtZSIsIk1vbGxpayJd~","decodedPayload":{"iat":1712092475525,"iss":"Issuer","vct":"Identity","jti":"71690b92-b253-48ab-8e67-21dc037b6af4","cnf":{"kid":"did:jwk:eyJrdHkiOiJFQyIsIngiOiJBcXRBc3VQQ2syYWxrcUk0ZFFiUGZBZGZtM0syLTYtcUlOVERyaFhhREk0IiwieSI6IlhBUUhvS0VteGZtbVFWRWhCLUpYU1pLWEVkRGJ5akpiTFZpNVllQ0FoTzAiLCJjcnYiOiJQLTI1NiJ9#0"},"prename":"Mirko","surname":"Mollik"},"disclosures":[{"decoded":["afa738693392e917","prename","Mirko"],"digest":"GDtB0y89g4f32AyHsSax7JGl06VHeWb1eZ3eyhgGl7E","encoded":"WyJhZmE3Mzg2OTMzOTJlOTE3IiwicHJlbmFtZSIsIk1pcmtvIl0"},{"decoded":["5771b8b009c31333","surname","Mollik"],"digest":"lunsB2ykzPTJ0wCJbVgvZZWplQI-8ZgEmP65v_Z97R0","encoded":"WyI1NzcxYjhiMDA5YzMxMzMzIiwic3VybmFtZSIsIk1vbGxpayJd"}],"signedPayload":{"iat":1712092475525,"iss":"Issuer","vct":"Identity","jti":"71690b92-b253-48ab-8e67-21dc037b6af4","cnf":{"kid":"did:jwk:eyJrdHkiOiJFQyIsIngiOiJBcXRBc3VQQ2syYWxrcUk0ZFFiUGZBZGZtM0syLTYtcUlOVERyaFhhREk0IiwieSI6IlhBUUhvS0VteGZtbVFWRWhCLUpYU1pLWEVkRGJ5akpiTFZpNVllQ0FoTzAiLCJjcnYiOiJQLTI1NiJ9#0"},"_sd":["GDtB0y89g4f32AyHsSax7JGl06VHeWb1eZ3eyhgGl7E","lunsB2ykzPTJ0wCJbVgvZZWplQI-8ZgEmP65v_Z97R0"],"_sd_alg":"SHA-256"}}

isdecoded true
isEncoded false

So is the intention of if (credentials.some((c) => CredentialMapper.isSdJwtDecodedCredential(c) || CredentialMapper.isSdJwtEncoded(c))) { to only get the sd-jwt-vc credentials, the error seems to be here.

To avoid the hash call in the function, we need to pass the pre calculated sdHash in the SdJwtDecodedVerifiableCredential object.

Or we just make the hasher call async since PresentationExchange.findValidPresentationDefinitions is already async :)

[TimoGlastra]

Hmm yeah that's a good one. as mentioned in the other issue, I'm fine with making things async 👍

Passing the sdHash is getting very complex, and in that case it'd be better to construct the KB-JWT outside of the PEX library

[cre8]

In case we can solve issue #147 by passing an async hash function, we can calculate everything inside the pex function and do not need changes like in this issue. So when the other issue is resolved, we can close this one