This class is meant to authenticate users and store authentication session identifiers in cookies.
The class is also capable of managing the list of authorized users in a file stored in the server.
The authentication identifier contains an hash value that is stored in user computer by the means of cookies. The hash value is also stored on a temporary file on the server to verify that the authenticity of the user. This is meant to prevent that unauthorized users forge authentication cookies, thus making the system more secure.