RP state definition

docs/en/remote-flow.rst

@@ -148,6 +148,8 @@ response, containing the request URI, are described in the Table below.
     - REQUIRED. The HTTPs URL where the Relying Party provides the signed Request Object to the Wallet Instance.
   * - **client_id_scheme**
     - OPTIONAL. The scheme used by the Relying Party for the client_id, detailing the format and structure and the trust evaluation method. It SHOULD be set with ``entity_id``.
+  * - **state**
+    - OPTIONAL. A unique identifier for the current transaction generated by the Relying Party. The value SHOULD be opaque to the Wallet Instance.
   * - **request_uri_method**
     - OPTIONAL. The HTTP method MUST be set with ``get`` or ``post``. The Wallet Instance should use this method obtain the signed Request Object from the request_uri. If not provided, the Wallet Instance SHOULD use the HTTP method ``get``. If provided, the Wallet Instance SHOULD provide its metadata within the HTTP POST body encoded in ``application/json``.