gistfile1.txt

public object DoSomething(string jsonString) {
	var json = DeserializeJson(jsonString);
	var dict = json as IDictionary<string, object>;
	if(dict == nul) {
		// use another serializer to normalize the json
		// and set dict.
	} else {
		// DeserializeJson worked so do nothing. 
	}
	var algorithm = (string)envelope["algorithm"];
	// some validation stuff here
	return json;
}

dynamic result = DoSomething(jsonString);
string algorithm = result.algorithm;