+Data schemas are useful when enforcing a specific structure on a given +collection of data. There are at least two types of data schemas that this +specification considers: +
+ ++It is important to understand that data schemas serve a different purpose from +the `@context` property, which neither enforces data structure or +data syntax, nor enables the definition of arbitrary encodings to alternate +representation formats. +
++This specification defines the following [=property=] for the expression of a +data schema, which can be included by an [=issuer=] in +the [=verifiable credentials=] that it issues: +
+ ++The value of the `credentialSchema` [=property=] MUST be one or +more data schemas that provide [=verifiers=] with enough information to +determine whether the provided data conforms to the provided schema(s). Each +`credentialSchema` MUST specify its `type` (for example, +`JsonSchema`), and an `id` [=property=] +that MUST be a [=URL=] identifying the schema file. The precise contents of +each data schema is determined by the specific type definition. +
++If multiple schemas are present, validity is determined according to the +processing rules outlined by each associated `credentialSchema` +`type` property. +
++The `credentialSchema` [=property=] provides an opportunity to +annotate type definitions or lock them to specific versions of the vocabulary. +Authors of [=verifiable credentials=] can include a static version of their +vocabulary using `credentialSchema` that is locked to some content +integrity protection mechanism. The `credentialSchema` +[=property=] also makes it possible to perform syntactic checking on the +[=credential=] and to use [=verification=] mechanisms such as JSON Schema +[[?VC-JSON-SCHEMA]] validation. +
+ +
+{
+ "@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", "ExamplePersonCredential"],
+ "issuer": "https://university.example/issuers/14",
+ "validFrom": "2010-01-01T19:23:24Z",
+ "credentialSubject": {
+ "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
+ "degree": {
+ "type": "ExampleBachelorDegree",
+ "name": "Bachelor of Science and Arts"
+ },
+ "alumniOf": {
+ "name": "Example University"
+ }
+ },
+ "credentialSchema": [{
+ "id": "https://example.org/examples/degree.json",
+ "type": "JsonSchema"
+ },
+ {
+ "id": "https://example.org/examples/alumni.json",
+ "type": "JsonSchema"
+ }]
+}
+
+
+ +In the example above, the [=issuer=] is specifying a +`credentialSchema`, which points to a [[?VC-JSON-SCHEMA]] file that +can be used by a [=verifier=] to determine whether the +[=verifiable credential=] is well-formed. +
+ ++For information about linkages to JSON Schema [[?VC-JSON-SCHEMA]] or other +optional schema validation mechanisms, see the [[[VC-IMP-GUIDE]]] document. +
+ ++Data schemas can also be used to specify mappings to other formats, such as +those used to perform zero-knowledge proofs. For more information on using the +`credentialSchema` [=property=] with zero-knowledge proofs, +see Section [[[#zero-knowledge-proofs]]]. +
+ +
+{
+ "@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",
+ "credentialSubject": {
+ "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
+ "degree": {
+ "type": "ExampleBachelorDegree",
+ "name": "Bachelor of Science and Arts"
+ }
+ },
+ "credentialSchema": {
+ "id": "https://example.org/examples/degree",
+ "type": "ZkpExampleSchema2018"
+ }
+}
+
+
+ +In the example above, the [=issuer=] is specifying a +`credentialSchema` pointing to a means of transforming the input data +into a format which can then be used by a [=verifier=] to determine whether +the proof provided with the [=verifiable credential=] is well-formed. +
+ + +-Data schemas are useful when enforcing a specific structure on a given -collection of data. There are at least two types of data schemas that this -specification considers: -
- --It is important to understand that data schemas serve a different purpose from -the `@context` property, which neither enforces data structure or -data syntax, nor enables the definition of arbitrary encodings to alternate -representation formats. -
--This specification defines the following [=property=] for the expression of a -data schema, which can be included by an [=issuer=] in -the [=verifiable credentials=] that it issues: -
- --The value of the `credentialSchema` [=property=] MUST be one or -more data schemas that provide [=verifiers=] with enough information to -determine whether the provided data conforms to the provided schema(s). Each -`credentialSchema` MUST specify its `type` (for example, -`JsonSchema`), and an `id` [=property=] -that MUST be a [=URL=] identifying the schema file. The precise contents of -each data schema is determined by the specific type definition. -
--If multiple schemas are present, validity is determined according to the -processing rules outlined by each associated `credentialSchema` -`type` property. -
--The `credentialSchema` [=property=] provides an opportunity to -annotate type definitions or lock them to specific versions of the vocabulary. -Authors of [=verifiable credentials=] can include a static version of their -vocabulary using `credentialSchema` that is locked to some content -integrity protection mechanism. The `credentialSchema` -[=property=] also makes it possible to perform syntactic checking on the -[=credential=] and to use [=verification=] mechanisms such as JSON Schema -[[?VC-JSON-SCHEMA]] validation. -
- -
-{
- "@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", "ExamplePersonCredential"],
- "issuer": "https://university.example/issuers/14",
- "validFrom": "2010-01-01T19:23:24Z",
- "credentialSubject": {
- "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
- "degree": {
- "type": "ExampleBachelorDegree",
- "name": "Bachelor of Science and Arts"
- },
- "alumniOf": {
- "name": "Example University"
- }
- },
- "credentialSchema": [{
- "id": "https://example.org/examples/degree.json",
- "type": "JsonSchema"
- },
- {
- "id": "https://example.org/examples/alumni.json",
- "type": "JsonSchema"
- }]
-}
-
-
- -In the example above, the [=issuer=] is specifying a -`credentialSchema`, which points to a [[?VC-JSON-SCHEMA]] file that -can be used by a [=verifier=] to determine whether the -[=verifiable credential=] is well-formed. -
- --For information about linkages to JSON Schema [[?VC-JSON-SCHEMA]] or other -optional schema validation mechanisms, see the [[[VC-IMP-GUIDE]]] document. -
- --Data schemas can also be used to specify mappings to other formats, such as -those used to perform zero-knowledge proofs. For more information on using the -`credentialSchema` [=property=] with zero-knowledge proofs, -see Section [[[#zero-knowledge-proofs]]]. -
- -
-{
- "@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",
- "credentialSubject": {
- "id": "did:example:ebfeb1f712ebc6f1c276e12ec21",
- "degree": {
- "type": "ExampleBachelorDegree",
- "name": "Bachelor of Science and Arts"
- }
- },
- "credentialSchema": {
- "id": "https://example.org/examples/degree",
- "type": "ZkpExampleSchema2018"
- }
-}
-
-
- -In the example above, the [=issuer=] is specifying a -`credentialSchema` pointing to a means of transforming the input data -into a format which can then be used by a [=verifier=] to determine whether -the proof provided with the [=verifiable credential=] is well-formed. -
- - -