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Create the credential schema

The Identus Platform exposes REST API for creation, fetching, and searching the credential schema records.

The OpenAPI specification and ReDoc documentation describe the endpoint.

In this document, you can find step-by-step instructions for creating the credential schema.

Step-by-step guide​

The following guide demonstrates how to create a driving license credential schema.

1. Define the JSON Schema for the Verifiable Credential​

Assume that you need a credential schema for the driving license, and the verifiable credential must have the following fields:

  • emailAddress - the email address of the driver
  • givenName - the first name of the driver
  • familyName - the family name of the driver
  • dateOfIssuance - date of the driver's license issuance
  • drivingLicenseID - ID of the driving license
  • drivingClass - driving class that denotes which types of vehicles the driver is allowed to go. Also, let's assume that the driving license might have additional optional claims.

For the above fields, the JSON Schema definition must be:

{
  "$id": "https://example.com/driving-license-1.0.0",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "description": "Driving License",
  "type": "object",
  "properties": {
    "emailAddress": {
      "type": "string",
      "format": "email"
    },
    "givenName": {
      "type": "string"
    },
    "familyName": {
      "type": "string"
    },
    "dateOfIssuance": {
      "type": "string",
      "format": "date-time"
    },
    "drivingLicenseID": {
      "type": "string"
    },
    "drivingClass": {
      "type": "integer"
    }
  },
  "required": [
    "emailAddress",
    "familyName",
    "dateOfIssuance",
    "drivingLicenseID",
    "drivingClass"
  ],
  "additionalProperties": true
}

The fields $id and $schema must correspond values that describe

  • the identity of the given JSON Schema as a correctly formatted URL https://example.com/driving-license-1.0.0 and
  • the meta schema fixed to https://json-schema.org/draft/2020-12/schema which is the only supported value

All the claims are listed under the properties object with corresponding types and formats according to JSON Specification.

additionalProperties is set to true, meaning adding other fields to the verifiable credential is possible.

2. Create the credential schema record​

  1. Open your preferred REST API client, such as Postman or Insomnia, or use the client stub generated based on the OpenAPI specification.

  2. In the client, create a new POST request to the /cloud-agent/schema-registry/schemas endpoint.

Note that the value of the author field must match the short form of a PRISM DID that has been created using the same agent. An unpublished DID is sufficient. Please refer to the Create DID documentation page for more details on how to create a PRISM DID.

In the request body, create a JSON object:

{
  "name": "driving-license",
  "version": "1.0.0",
  "description": "Driving License Schema",
  "type": "https://w3c-ccg.github.io/vc-json-schemas/schema/2.0/schema.json",
  "author": "did:prism:4a5b5cf0a513e83b598bbea25cd6196746747f361a73ef77068268bc9bd732ff",
  "tags": [
    "driving",
    "license"
  ],
  "schema": {
    "$id": "https://example.com/driving-license-1.0.0",
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "description": "Driving License",
    "type": "object",
    "properties": {
      "emailAddress": {
        "type": "string",
        "format": "email"
      },
      "givenName": {
        "type": "string"
      },
      "familyName": {
        "type": "string"
      },
      "dateOfIssuance": {
        "type": "string",
        "format": "date-time"
      },
      "drivingLicenseID": {
        "type": "string"
      },
      "drivingClass": {
        "type": "integer"
      }
    },
    "required": [
      "emailAddress",
      "familyName",
      "dateOfIssuance",
      "drivingLicenseID",
      "drivingClass"
    ],
    "additionalProperties": true
  }
}
  1. Send the POST request to create the new schema. The response should contain a GUID that uniquely identifies the new schema. Curl example is the following:
curl -X 'POST' \
  'http://localhost:8080/cloud-agent/schema-registry/schemas' \
  -H 'accept: application/json' \
  -H "apikey: $API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "name": "driving-license",
  "version": "1.0.0",
  "description": "Driving License Schema",
  "type": "https://w3c-ccg.github.io/vc-json-schemas/schema/2.0/schema.json",
  "author": "did:prism:4a5b5cf0a513e83b598bbea25cd6196746747f361a73ef77068268bc9bd732ff",
  "tags": [
    "driving",
    "license"
  ],
  "schema": {
    "$id": "https://example.com/driving-license-1.0.0",
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "description": "Driving License",
    "type": "object",
    "properties": {
      "emailAddress": {
        "type": "string",
        "format": "email"
      },
      "givenName": {
        "type": "string"
      },
      "familyName": {
        "type": "string"
      },
      "dateOfIssuance": {
        "type": "string",
        "format": "date-time"
      },
      "drivingLicenseID": {
        "type": "string"
      },
      "drivingClass": {
        "type": "integer"
      }
    },
    "required": [
      "emailAddress",
      "familyName",
      "dateOfIssuance",
      "drivingLicenseID",
      "drivingClass"
    ],
    "additionalProperties": true
  }
}'

...and response might be the following:

{
  "guid": "3f86a73f-5b78-39c7-af77-0c16123fa9c2",
  "id": "f2bfbf78-8bd6-4cc6-8b39-b3a25e01e8ea",
  "longId": "did:prism:agent/f2bfbf78-8bd6-4cc6-8b39-b3a25e01e8ea?version=1.0.0",
  "name": "driving-license",
  "version": "1.0.0",
  "description": "Driving License Schema",
  "type": "https://w3c-ccg.github.io/vc-json-schemas/schema/2.0/schema.json",
  "author": "did:prism:4a5b5cf0a513e83b598bbea25cd6196746747f361a73ef77068268bc9bd732ff",
  "authored": "2023-03-14T14:41:46.713943Z",
  "tags": [
    "driving",
    "license"
  ],
  "schema": {
    "$id": "https://example.com/driving-license-1.0.0",
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "description": "Driving License",
    "type": "object",
    "properties": {
      "emailAddress": {
        "type": "string",
        "format": "email"
      },
      "givenName": {
        "type": "string"
      },
      "familyName": {
        "type": "string"
      },
      "dateOfIssuance": {
        "type": "string",
        "format": "date-time"
      },
      "drivingLicenseID": {
        "type": "string"
      },
      "drivingClass": {
        "type": "integer"
      }
    },
    "required": [
      "emailAddress",
      "familyName",
      "dateOfIssuance",
      "drivingLicenseID",
      "drivingClass"
    ],
    "additionalProperties": true
  },
  "kind": "CredentialSchema",
  "self": "/schema-registry/schemas/3f86a73f-5b78-39c7-af77-0c16123fa9c2"
}

3. Retrieve the created schema​

To retrieve the newly created schema, create a new GET request to the /cloud-agent/schema-registry/schemas/{guid} endpoint, where {guid} is the GUID returned in the response from the previous step. Send the GET request to retrieve the schema. Curl example is the following:

curl -X 'GET' \
  'http://localhost:8080/cloud-agent/schema-registry/schemas/3f86a73f-5b78-39c7-af77-0c16123fa9c2' \
  -H 'accept: application/json' \
  -H "apikey: $API_KEY"

The response should contain the JSON object representing the schema you just created.

{
  "guid": "3f86a73f-5b78-39c7-af77-0c16123fa9c2",
  "id": "f2bfbf78-8bd6-4cc6-8b39-b3a25e01e8ea",
  "longId": "did:prism:agent/f2bfbf78-8bd6-4cc6-8b39-b3a25e01e8ea?version=1.0.0",
  "name": "driving-license",
  "version": "1.0.0",
  "description": "Driving License Schema",
  "type": "https://w3c-ccg.github.io/vc-json-schemas/schema/2.0/schema.json",
  "author": "did:prism:4a5b5cf0a513e83b598bbea25cd6196746747f361a73ef77068268bc9bd732ff",
  "authored": "2023-03-14T14:41:46.713943Z",
  "tags": [
    "driving",
    "license"
  ],
  "schema": {
    "$id": "https://example.com/driving-license-1.0.0",
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "description": "Driving License",
    "type": "object",
    "properties": {
      "emailAddress": {
        "type": "string",
        "format": "email"
      },
      "givenName": {
        "type": "string"
      },
      "familyName": {
        "type": "string"
      },
      "dateOfIssuance": {
        "type": "string",
        "format": "date-time"
      },
      "drivingLicenseID": {
        "type": "string"
      },
      "drivingClass": {
        "type": "integer"
      }
    },
    "required": [
      "emailAddress",
      "familyName",
      "dateOfIssuance",
      "drivingLicenseID",
      "drivingClass"
    ],
    "additionalProperties": true
  },
  "kind": "CredentialSchema",
  "self": "/schema-registry/schemas/3f86a73f-5b78-39c7-af77-0c16123fa9c2"
}

The Cloud Agent instance's triple author, id, and version are unique. So, having a single DID reference that the author uses, creating the credential schema with the same id and version is impossible.

4. Update the credential schema​

To upgrade the credential schema, you need to perform the following steps:

  1. Start from the first step and change the JSON Schema
  2. Change the version according to the nature of your change
  3. Create a new credential schema record with a higher version