diff --git a/specification/graphrbac/data-plane/stable/1.6/graphrbac.json b/specification/graphrbac/data-plane/stable/1.6/graphrbac.json
index 7e1161f1bf38..b9006f6ef695 100644
--- a/specification/graphrbac/data-plane/stable/1.6/graphrbac.json
+++ b/specification/graphrbac/data-plane/stable/1.6/graphrbac.json
@@ -1942,6 +1942,11 @@
         "type": {
           "type": "string",
           "description": "Type. Acceptable values are 'AsymmetricX509Cert' and 'Symmetric'."
+        },
+        "customKeyIdentifier": {
+          "type":"string",
+          "format": "byte",
+          "description": "Custom Key Identifier"
         }
       },
       "additionalProperties": {