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

name: "w3c-vcdm-validity-period" description: "Use when implementing temporal validity in W3C VCDM. Covers: validity period semantics and related processing rules." sections: - "4.9 Validity Period"

4.9 Validity Period

This specification defines the validFrom property to help an issuer to express the date and time when a credential becomes valid and the validUntil property to express the date and time when a credential ceases to be valid.

When comparing dates and times, the calculation is done "temporally", meaning that the string value is converted to a "temporal value" which exists as a point on a timeline. Temporal comparisons are then performed by checking to see where the date and time being compared are in relation to a particular point on the timeline.

      validFrom

If present, the value of the validFrom property MUST be a [XMLSCHEMA11-2] dateTimeStamp string value representing the date and time the credential becomes valid, which could be a date and time in the future or the past. Note that this value represents the earliest point in time at which the information associated with the credentialSubject property becomes valid. If a validUntil value also exists, the validFrom value MUST express a point in time that is temporally the same or earlier than the point in time expressed by the validUntil value.

      validUntil

If present, the value of the validUntil property MUST be a [XMLSCHEMA11-2] dateTimeStamp string value representing the date and time the credential ceases to be valid, which could be a date and time in the past or the future. Note that this value represents the latest point in time at which the information associated with the credentialSubject property is valid. If a validFrom value also exists, the validUntil value MUST express a point in time that is temporally the same or later than the point in time expressed by the validFrom value.

[Example 11](https://www.w3.org/TR/vc-data-model-2.0/#example-use-of-the-validfrom-and-validuntil-properties): Use of the validFrom and validUntil properties

  - 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/14", "validFrom": "2010-01-01T19:23:24Z", "validUntil": "2020-01-01T19:23:24Z", "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/14",
  "validFrom": "2010-01-01T19:23:24Z",
  "validUntil": "2020-01-01T19:23:24Z",
  "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": "z65sN9W58eruTDUUXYxxwhG4cQ73zQkQuhMYvUVipeM4oEUBPbCxd3oTQTJhnfHN9juyZSzYpERYFjZcfpb2xgeto"
  }
}
```**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/14",
  "validFrom": "2010-01-01T19:23:24Z",
  "validUntil": "2020-01-01T19:23:24Z",
  "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": "u2V0AhVhAxWvPP0HD9usaRDFthqpz1zXbWtTpNr_1pRFMKY9wbt7RAh0kwkoqR9cFHY0PdBj0cPo9BXd_54Z9iLl7GsmAjlgjgCQCJ0FUx3YRbBxybCrTEtFINFNKD7UC2j8tjmvYa6EQKlNYIL-KVtIrAWQi98Ng86FB4giy2xKCqn_kNOmO75D7AQfEhlhA5pKNMOahYQbk8obEMFyLgAsmd3FGqf3FoDTojybRWUPf7F3A22Kl1822zW093-XtKum7Nfe3q16norHXUnhkWVhAvNR9By8I5ISJtylSp1fkzurbIvSXVhkaj4wsUpbTy1GnYHzeS7qhAyUoO4GkIMUfP3yLS0BIGBbJR7de1s5G4lhATnwFdztYAEXk6z93jJot3TPhlnOYk10G0e7u3uyJJF-ZrAsctOYbjF3ZcNZu3UXJZRe4_ytxr5OqwIVLnUfDqFhAkff2_b4hqpz0uK0kDHjkpMun4mAhuxVCjcmyIlJnaaTdFc2RovLnKiPx4Xnd9P_lOd3ZQoz5ThPWzMS7r_43M1hAmVVtNJ7-lpJdlc9tg5e3GpAhnXzYHpiv3WRRT3F4tH8B_zkHnyeNBT61d16TTnvlFn5mFXJ99FD4abIcQkyP_lhA8IS9pAGKqVgTDzxXSvGcGWMXQ4LEy3jfywyDpdiZodvttNhuZVBMkGKhNBo94oGjIHRfoeAFvQfZQo8_ENtBEYFnL2lzc3Vlcg"
  }
}
```**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/14",
  "validFrom": "2010-01-01T19:23:24Z",
  "validUntil": "2020-01-01T19:23:24Z",
  "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": "u2V0ChVhQjBPG4AXIRGKu6h5awRiAZHSrx5gfUdbWc2rAxdsfIzSIywzsphRnlb5rPDWwdJlBF5krx4JRYNtT7exHHAw_aZtO6AARXGfbz0eHNrcTKL5YQGd_DaMQQsoaryttl5TvxnFT-Vm4SkVx03K9qNJ4jhArKnv3N5iX7nvZR0OCXS-uXH4QQ9mW65QM5qlHOfE4GQVYYJVTGbTfcflzyx41E-f9kSqmf10xYzxJrGfC7b7GPY8X7VjMT__ZKSuwdH-5jak-5gkjocsHI6oxIKlLrhW1Wh5yrDCH-QC823TS8NE9VGBzIFAfUt5qazGEcJ8CxeSPxFggWjulaLj5whA4VZOvBqHQbwhSW7Ph0eZ2bxz7ota_qnCBZy9pc3N1ZXI"
  }
}

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/14",
  "validFrom": "2010-01-01T19:23:24Z",
  "validUntil": "2020-01-01T19:23:24Z",
  "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/14",
  "validFrom": "2010-01-01T19:23:24Z",
  "validUntil": "2020-01-01T19:23:24Z",
  "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/14",  "validFrom": "2010-01-01T19:23:24Z",  "validUntil": "2020-01-01T19:23:24Z",  "credentialSubject": {    "degree": {      "name": "Bachelor of Science and Arts",      "_sd": [        "tkx6UW3wT_NqTixvVGkswdZF-kBA4NhAWZGJlaQDiDI"      ]    },    "_sd": [      "fNjDSDHl3HBCSCXRG8t9bnwTH1JSOBP8M0ZaZBZPNcI"    ]  },  "_sd": [    "PxSvcLzZojmKrNj1eJX3qV6JqZ1tPUWWX0Z9CgKE9DU",    "tSI8HzYX7dXtxi1W7Pu1rH8KvE5LAFCDUSqpzlngsD8"  ]}