C# - encrypt class structure into file.

Currently, I write an instance of class Setups into a file using XML serialization.  And I will read the instance back when my application startup.  I use result of the  XML serialization as the configuration file of my application.

Now I would like to encrypt the result of the xml serialization and able to read it back into a class instance.

Currently.

Save configuration
class instance -->XML Serialization --> write XML file
Read configuraiont
Read XML File  --> XML Serialization --> class instance

Now I am hoping to incorporate encrypt/decrypt

Save configuration
class instance  -->XML Serialization -->  encrypt --> write XML file
Read configuraiont
Read XML File  --> decrypt --> XML Serialization --> class instance

Is this the right way to be expected or what is the right steps? And any good tutorial and examples for this type of operation?

Below is the class I try to do.

   [XmlRootAttribute("Setups", IsNullable = false)]
    public class Setups
    {
        public int TradeType;

        //[XmlArrayItem]
        [XmlElement("Setup")]
        public Setup[] Setup;
     }

    public class Setup
    {

        [XmlAttribute("entry")]         public int _entry;
        [XmlAttribute("type")]          public string _typeString;
        [XmlIgnore]                             public string _type;
       [XmlElement("Name")]         public string _name;
       [XmlElement("Entry")]           public string _entryName;
    }