This enumeration specifies how ASP.NET protects the Forms Authentication cookie. It is not used in ASP.NET code, but in the web.config file by the protection attribute of the forms element (for example, <forms name="name" loginUrl="url" protection="None ">). Encryption uses Triple-DES or DES to encode the cookie before it is transmitted. Validation verifies the cookie hasn't been altered in transit by appending a validation key and then a Message Authentication Code (MAC) to the cookie.
public enum FormsProtectionEnum { All = 0, None = 1, Encryption = 2, Validation = 3 }