w3c-vcdm-subject-validity - SKILL.md Agent Skill

name: "w3c-vcdm-subject-validity" description: "Use when modeling credential subject data in W3C VCDM. Covers: credentialSubject structure and semantics." sections: - "4.8 Credential Subject"

4.8 Credential Subject

A verifiable credential contains claims about one or more subjects. This specification defines a credentialSubject property for the expression of claims about one or more subjects.

A verifiable credential MUST contain a credentialSubject property.

      credentialSubject

The value of the credentialSubject property is a set of objects where each object MUST be the subject of one or more claims, which MUST be serialized inside the credentialSubject property. Each object MAY also contain an id property to identify the subject, as described in Section 4.4 Identifiers.

[Example 9](https://www.w3.org/TR/vc-data-model-2.0/#example-use-of-the-credentialsubject-property): Use of the credentialSubject property

  - Credential- ecdsa- ecdsa-sd- bbs- jose- cose- sd-jwt```

{ "@context": [ "https://www.w3.org/ns/credentials/v2", "https://www.w3.org/ns/credentials/examples/v2" ], "id": "http://university.example/credentials/3732", "type": ["VerifiableCredential", "ExampleDegreeCredential"], "issuer": "https://university.example/issuers/565049", "validFrom": "2010-01-01T00:00:00Z", "credentialSubject": { "id": "did:example:ebfeb1f712ebc6f1c276e12ec21", "degree": { "type": "ExampleBachelorDegree", "name": "Bachelor of Science and Arts" } } }

            ```
{
  "@context": [
    "https://www.w3.org/ns/credentials/v2",
    "https://www.w3.org/ns/credentials/examples/v2"
  ],
  "id": "http://university.example/credentials/3732",
  "type": [
    "VerifiableCredential",
    "ExampleDegreeCredential"
  ],
  "issuer": "https://university.example/issuers/565049",
  "validFrom": "2010-01-01T00:00:00Z",
  "credentialSubject": {
    "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
    "degree": {
      "type": "ExampleBachelorDegree",
      "name": "Bachelor of Science and Arts"
    }
  },
  "proof": {
    "type": "DataIntegrityProof",
    "created": "2025-04-27T17:58:34Z",
    "verificationMethod": "did:key:zDnaebSRtPnW6YCpxAhR5JPxJqt9UunCsBPhLEtUokUvp87nQ",
    "cryptosuite": "ecdsa-rdfc-2019",
    "proofPurpose": "assertionMethod",
    "proofValue": "z36CTYymphefPFDdFakYBe7EHHX7Upev5vtRhxG3ZtKiUPXFKknW9ZTds3wxDhTz1WFCGzFUUv6DC5vifg3VCCSFL"
  }
}
```**application/vc**
            ```
{
  "@context": [
    "https://www.w3.org/ns/credentials/v2",
    "https://www.w3.org/ns/credentials/examples/v2"
  ],
  "id": "http://university.example/credentials/3732",
  "type": [
    "VerifiableCredential",
    "ExampleDegreeCredential"
  ],
  "issuer": "https://university.example/issuers/565049",
  "validFrom": "2010-01-01T00:00:00Z",
  "credentialSubject": {
    "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
    "degree": {
      "type": "ExampleBachelorDegree",
      "name": "Bachelor of Science and Arts"
    }
  },
  "proof": {
    "type": "DataIntegrityProof",
    "created": "2025-04-27T17:58:34Z",
    "verificationMethod": "did:key:zDnaerJh8WwyBVVGcZKKkqRKK9iezje8ut6t9bnNChtxcWwNv",
    "cryptosuite": "ecdsa-sd-2023",
    "proofPurpose": "assertionMethod",
    "proofValue": "u2V0AhVhAFPsovbuHDInv8ft0M6jMPGrLrNs9j_sEfn1gdDCxFOmyjYDyblufuagmARZj9RabxfO0SkbpUi_m6dQdXIyoklgjgCQC78Ayc-2ykLAZ_NJzb5-S8dtSenHeKEHHGy469czIbhtYILJ97_OhxkzZccWMaUgCAXRO5ZCyoagriazYdV2ViFsuhVhAvGcG2tqQoB5VaC-x652sos00_94wzBOZg9wGR2mytwn_alXEbksbCMUC2lmiU_FrcFzEEAZrAdcsAfoE0J_KRlhAc71QXbdP2iKlqmgocH4qvDcv_3PT_VmSFGWISFdrQPkmv2lb2r9Mb02yZYilf20oMzCPCRsqYP--0g8ysm9doVhAIqwWkfg1pXXKaxx4_5_QpmoOoXjLPNhJ-14QSHUyxTKKCTarm33OdaIhhCjm5_e7MUCYHvA89vCSvSHMrKvKclhASFp1GivaJXYrbBcM6xNFNsXW7xBg7cZXfBeGOwcXf7fXg1GwMJILZBimOaEM5Eay38F8T6HwbeuMvBQ7b05gbFhAkLeI8-tdeQQzX6ik0xDSM4yLsHPmhG47Tu5Hm25ujoo9iVsLzskiGcIsQLsqvRK5238FvPQAeOpK04R7F2aK9IFnL2lzc3Vlcg"
  }
}
```**application/vc**
            ```
{
  "@context": [
    "https://www.w3.org/ns/credentials/v2",
    "https://www.w3.org/ns/credentials/examples/v2"
  ],
  "id": "http://university.example/credentials/3732",
  "type": [
    "VerifiableCredential",
    "ExampleDegreeCredential"
  ],
  "issuer": "https://university.example/issuers/565049",
  "validFrom": "2010-01-01T00:00:00Z",
  "credentialSubject": {
    "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
    "degree": {
      "type": "ExampleBachelorDegree",
      "name": "Bachelor of Science and Arts"
    }
  },
  "proof": {
    "type": "DataIntegrityProof",
    "verificationMethod": "did:key:zUC78GzFRA4TWh2mqRiKro1wwRb5KDaMJ3M1AD3qGtgEbFrwWGvWbnCzArkeTZCyzBz4Panr2hLaZxsXHiBQCwBc3fRPH6xY4u5v8ZAd3dPW1aw89Rra86CVwXr3DczANggYbMD",
    "cryptosuite": "bbs-2023",
    "proofPurpose": "assertionMethod",
    "proofValue": "u2V0ChVhQkkdBby2GbmvVh66cM6TNzNfh0hR9ePeG7dWYbHfDxK6CcA_rVoxxsRGIoWX5Gs6ZGgQNPTBeehiEHT_cj-5fjZ6ArTluARHPbaXQzWyXKrVYQGd_DaMQQsoaryttl5TvxnFT-Vm4SkVx03K9qNJ4jhArS1r7HKFDPyyrvPGqNF8bjgNELvoomOjpbD9JEvaGI1pYYJVTGbTfcflzyx41E-f9kSqmf10xYzxJrGfC7b7GPY8X7VjMT__ZKSuwdH-5jak-5gkjocsHI6oxIKlLrhW1Wh5yrDCH-QC823TS8NE9VGBzIFAfUt5qazGEcJ8CxeSPxFggUfIz7Xi8QhNU6pC7qIkL0HkvpKYuV2rzBuKizKrBhU6BZy9pc3N1ZXI"
  }
}

Protected Headers

{
  "kid": "ExHkBMW9fmbkvV266mRpuP2sUY_N_EWIN1lapUzO8ro",
  "alg": "ES256"
}

application/vc

{
  "@context": [
    "https://www.w3.org/ns/credentials/v2",
    "https://www.w3.org/ns/credentials/examples/v2"
  ],
  "id": "http://university.example/credentials/3732",
  "type": [
    "VerifiableCredential",
    "ExampleDegreeCredential"
  ],
  "issuer": "https://university.example/issuers/565049",
  "validFrom": "2010-01-01T00:00:00Z",
  "credentialSubject": {
    "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
    "degree": {
      "type": "ExampleBachelorDegree",
      "name": "Bachelor of Science and Arts"
    }
  }
}

application/vc+jwt

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application/vc

{
  "@context": [
    "https://www.w3.org/ns/credentials/v2",
    "https://www.w3.org/ns/credentials/examples/v2"
  ],
  "id": "http://university.example/credentials/3732",
  "type": [
    "VerifiableCredential",
    "ExampleDegreeCredential"
  ],
  "issuer": "https://university.example/issuers/565049",
  "validFrom": "2010-01-01T00:00:00Z",
  "credentialSubject": {
    "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
    "degree": {
      "type": "ExampleBachelorDegree",
      "name": "Bachelor of Science and Arts"
    }
  }
}

application/vc+cose

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  - 
    Encoded
  
  - 
    Decoded
  
  - 
    Issuer Disclosures

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```

{ "kid": "ExHkBMW9fmbkvV266mRpuP2sUY_N_EWIN1lapUzO8ro", "alg": "ES256"}

      ```
{  "iat": 1745776714,  "exp": 1746986314,  "_sd_alg": "sha-256",  "@context": [    "https://www.w3.org/ns/credentials/v2",    "https://www.w3.org/ns/credentials/examples/v2"  ],  "issuer": "https://university.example/issuers/565049",  "validFrom": "2010-01-01T00:00:00Z",  "credentialSubject": {    "degree": {      "name": "Bachelor of Science and Arts",      "_sd": [        "eSsD1uaqSneGHTEcMle3VsZRp8tMnj5CGr7Q3jwsvFk"      ]    },    "_sd": [      "aNL13g6u-zsvTmXVA_9TXuykIWiG7tv5olLstsbx9dk"    ]  },  "_sd": [    "Dl0zzxvIqp5MWA5a3I2PD1MArw6VA4QLydlqSlJEByY",    "jVkRi7K0e2I1dlRTEtDvQULB1qfZgsMpiBv5Pak21ys"  ]}