The class name of the implementation of this interface is configured in the gateway configuration's security section.

IPrincipal DoAuthentication(string username, Hashtable credentials)
The gateway calls this method to perform programmatic, custom authentication. The credentials are passed as a Hashtable to allow for extra properties to be passed in the future. For now, only a "password" property is sent.

bool DoAuthorization(IPrincipal principal, IList roles)
The gateway calls this method to perform programmatic authorization..

A typical implementation would simply iterate over the supplied roles:
foreach(string role in roles )
{
   if( principal.IsInRole(role) )
      return true;
}
return false;

bool Logout()
Attempts to log out the current user out from their session.

You can register a login command in the <security> section of the Flex services configuration file or in the <security> section of the web.config file (flash remoting only).