JSON Schema - include latest spec updates around CredSchema/digestSRI

credential/model.go

@@ -68,8 +68,9 @@ func (cs CredentialSubject) GetJSONSchema() map[string]any {
 }
 
 type CredentialSchema struct {
-	ID   string `json:"id" validate:"required"`
-	Type string `json:"type" validate:"required"`
+	ID        string `json:"id" validate:"required"`
+	Type      string `json:"type" validate:"required"`
+	DigestSRI string `json:"digestSRI,omitempty"`
 }
 
 type RefreshService struct {

credential/schema/model.go

@@ -13,6 +13,11 @@ const (
 	JSONSchemaType VCJSONSchemaType = "JsonSchema"
 	TypeProperty   string           = "type"
 
+	// Known CredentialSchema property values for JsonSchemaCredential
+
+	JSONSchemaCredentialSchemaID  = "https://www.w3.org/2022/credentials/v2/json-schema-credential-schema.json"
+	JSONSchemaCredentialDigestSRI = "sha384-S57yQDg1MTzF56Oi9DbSQ14u7jBy0RDdx0YbeV7shwhCS88G8SCXeFq82PafhCrW"
+
 	Draft202012 JSONSchemaVersion = "https://json-schema.org/draft/2020-12/schema"
 	Draft201909 JSONSchemaVersion = "https://json-schema.org/draft/2019-09/schema"
 	Draft7      JSONSchemaVersion = "https://json-schema.org/draft-07/schema#"

credential/schema/testdata/jsonschemacredential-schema-1.json

@@ -7,6 +7,11 @@
   "type": ["VerifiableCredential", "JsonSchemaCredential"],
   "issuer": "https://example.com/issuers/14",
   "issuanceDate": "2010-01-01T19:23:24Z",
+  "credentialSchema": {
+    "id": "https://www.w3.org/2022/credentials/v2/json-schema-credential-schema.json",
+    "type": "JsonSchema",
+    "digestSRI": "sha384-S57yQDg1MTzF56Oi9DbSQ14u7jBy0RDdx0YbeV7shwhCS88G8SCXeFq82PafhCrW"
+  },
   "credentialSubject": {
     "id": "https://example.com/schemas/email-credential-schema.json",
     "type": "JsonSchema",

credential/schema/vcjsonschema.go

@@ -48,23 +48,11 @@ func IsCredentialValidForJSONSchema(cred credential.VerifiableCredential, vcs VC
 		s = JSONSchema(vcs)
 		schemaID = s.ID()
 	case JSONSchemaCredentialType:
-		var vc credential.VerifiableCredential
-		schemaString := vcs.String()
-		if err := json.Unmarshal([]byte(schemaString), &vc); err != nil {
-			return errors.Wrap(err, "unmarshalling schema")
+		var err error
+		s, schemaID, err = parseJSONSchemaCredential(vcs)
+		if err != nil {
+			return errors.Wrap(err, "parsing credential schema")
 		}
-		schemaType, ok := vc.CredentialSubject[TypeProperty]
-		if !ok {
-			return errors.New("credential schema's credential subject does not contain a `type`")
-		}
-		if schemaType != JSONSchemaType.String() {
-			return fmt.Errorf("credential schema's credential subject type<%s> does not match schema type<%s>", schemaType, JSONSchemaType)
-		}
-		s = vc.CredentialSubject.GetJSONSchema()
-		if len(s) == 0 {
-			return errors.New("credential schema's credential subject does not contain a valid `jsonSchema`")
-		}
-		schemaID = vc.ID
 	}
 
 	// check the ID is a valid URI
@@ -100,6 +88,42 @@ func IsCredentialValidForJSONSchema(cred credential.VerifiableCredential, vcs VC
 	return nil
 }
 
+// JsonSchemaCredential helper for IsCredentialValidForJSONSchema
+func parseJSONSchemaCredential(vcs VCJSONSchema) (JSONSchema, string, error) {
+	var vc credential.VerifiableCredential
+	schemaString := vcs.String()
+	if err := json.Unmarshal([]byte(schemaString), &vc); err != nil {
+		return nil, "", errors.Wrap(err, "unmarshalling schema")
+	}
+	schemaType, ok := vc.CredentialSubject[TypeProperty]
+	if !ok {
+		return nil, "", errors.New("credential schema's credential subject does not contain a `type`")
+	}
+	if schemaType != JSONSchemaType.String() {
+		return nil, "", fmt.Errorf("credential schema's credential subject type<%s> does not match schema type<%s>", schemaType, JSONSchemaType)
+	}
+	if vc.CredentialSchema == nil {
+		return nil, "", errors.New("credential schema's credential subject does not contain a `credentialSchema`")
+	}
+	credSchema := vc.CredentialSchema
+	if credSchema.ID != JSONSchemaCredentialSchemaID {
+		return nil, "", fmt.Errorf("credential schema's credential schema id<%s> does not match known id<%s>", credSchema.ID, JSONSchemaCredentialSchemaID)
+	}
+	if credSchema.Type != JSONSchemaType.String() {
+		return nil, "", fmt.Errorf("credential schema's credential schema type<%s> does not match known type<%s>", credSchema.Type, JSONSchemaType)
+	}
+	if credSchema.DigestSRI != JSONSchemaCredentialDigestSRI {
+		return nil, "", fmt.Errorf("credential schema's credential schema digest sri<%s> does not match known sri<%s>", credSchema.DigestSRI, JSONSchemaCredentialDigestSRI)
+	}
+
+	s := vc.CredentialSubject.GetJSONSchema()
+	if len(s) == 0 {
+		return nil, "", errors.New("credential schema's credential subject does not contain a valid `jsonSchema`")
+	}
+	schemaID := vc.ID
+	return s, schemaID, nil
+}
+
 // GetCredentialSchemaFromCredential returns the credential schema and type for a given credential given
 // a credential schema access, which is used to retrieve the schema
 func GetCredentialSchemaFromCredential(access VCJSONSchemaAccess, cred credential.VerifiableCredential) (VCJSONSchema, VCJSONSchemaType, error) {

credential/schema/vcjsonschema_test.go

@@ -254,6 +254,66 @@ func TestIsCredentialValidForJSONSchema_JsonSchemaCredential(t *testing.T) {
 		})
 	})
 
+	t.Run("The value of the credentialSchema property MUST always be set to [known json schema]", func(t *testing.T) {
+		t.Run("valid credentialSchema", func(t *testing.T) {
+			cred := getTestVCJSONSchemaCredential()
+			schema := getTestVCJSONSchemaSchema()
+			err := IsCredentialValidForJSONSchema(cred, schema, JSONSchemaCredentialType)
+			assert.NoError(t, err)
+		})
+
+		t.Run("credentialSchema wrong id", func(t *testing.T) {
+			cred := getTestVCJSONSchemaCredential()
+			schema := getTestVCJSONSchemaSchema()
+			schema["credentialSchema"] = map[string]any{
+				"id":        "bad",
+				"type":      JSONSchemaType,
+				"digestSRI": JSONSchemaCredentialDigestSRI,
+			}
+			err := IsCredentialValidForJSONSchema(cred, schema, JSONSchemaCredentialType)
+			assert.Error(t, err)
+			assert.ErrorContains(t, err, "credential schema's credential schema id<bad> does not match known id")
+		})
+
+		t.Run("credentialSchema wrong type", func(t *testing.T) {
+			cred := getTestVCJSONSchemaCredential()
+			schema := getTestVCJSONSchemaSchema()
+			schema["credentialSchema"] = map[string]any{
+				"id":        JSONSchemaCredentialSchemaID,
+				"type":      "NotJsonSchema",
+				"digestSRI": JSONSchemaCredentialDigestSRI,
+			}
+			err := IsCredentialValidForJSONSchema(cred, schema, JSONSchemaCredentialType)
+			assert.Error(t, err)
+			assert.ErrorContains(t, err, "credential schema's credential schema type<NotJsonSchema> does not match known type<JsonSchema>")
+		})
+
+		t.Run("credentialSchema wrong digestSRI", func(t *testing.T) {
+			cred := getTestVCJSONSchemaCredential()
+			schema := getTestVCJSONSchemaSchema()
+			schema["credentialSchema"] = map[string]any{
+				"id":        JSONSchemaCredentialSchemaID,
+				"type":      JSONSchemaType,
+				"digestSRI": "bad",
+			}
+			err := IsCredentialValidForJSONSchema(cred, schema, JSONSchemaCredentialType)
+			assert.Error(t, err)
+			assert.ErrorContains(t, err, "credential schema's credential schema digest sri<bad> does not match known sri")
+		})
+
+		t.Run("credentialSchema missing digestSRI", func(t *testing.T) {
+			cred := getTestVCJSONSchemaCredential()
+			schema := getTestVCJSONSchemaSchema()
+			schema["credentialSchema"] = map[string]any{
+				"id":   JSONSchemaCredentialSchemaID,
+				"type": JSONSchemaType,
+			}
+			err := IsCredentialValidForJSONSchema(cred, schema, JSONSchemaCredentialType)
+			assert.Error(t, err)
+			assert.ErrorContains(t, err, "credential schema's credential schema digest sri<> does not match known sri")
+		})
+	})
+
 	t.Run("the $id property MUST be present and its value MUST represent a valid URI", func(t *testing.T) {
 		t.Run("$id is a valid URI", func(t *testing.T) {
 			cred := getTestVCJSONSchemaCredential()
@@ -385,6 +445,11 @@ func getTestVCJSONSchemaSchema() VCJSONSchema {
 				"required": []string{"credentialSubject"},
 			},
 		},
+		"credentialSchema": map[string]any{
+			"id":        JSONSchemaCredentialSchemaID,
+			"type":      "JsonSchema",
+			"digestSRI": JSONSchemaCredentialDigestSRI,
+		},
 	}
 }