A Hybrid Design for Cheat Detection in Massively Multiplayer Online

       
  

 
   
  
 
         
         
    
     

          
           
           
             
                
            
            
trade-off between security and network efciency.
            
             
            
             
           
            
             
      t and scalability from distributed
              
           




            
            
       ̀     
              
    ̀           
̀ ̀         ̀ 
              ̀ 
        ̀       
     e et l’efcacit
  ̀     ̀     
        ̀     
          
             
        ̀      
           ̀
           ̀   
        ̀    
 ̀            
     ̀      
 ̀               ̀
         


            
            










  

  

 

  


                                     

                                    
3 Cheat Classication


                            

                     

                        

                            

                                    

   


                              

                                 

                                

                                   

                                       
  



                          

                              

                           

                             

                            
                           
5.2.1
Denitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

                         

                           

                          
  


                             
6.2
Further Parameter Justication . . . . . . . . . . . . . . . . . . . .     

                         


                             

                         

               
                                

                          

                          

                            

  





                        
7.1.1
The Effects of Different Client Congurations . . . . . . . .     

                  

                          
                            

                           

                       
                          

                       

                           

                     
                          
  


                                

                            
 


  

   
                         


                              


                               

                                     

 

                               

                            

                            

                            

                          

         
7.1
The Effects on Different Client Congurations . . . . . . . . . .       

                         

                               

                               

                              

                              

                             

     

                       
                               


   
               

                       

                   

  

          
                                    

          
                                    

                        

                          

                          

                          

 

             
              
          
              
             
              
                
                
                
               
              
              
low costs, which increases prot margins. It also allows for    
            
           
              
             
              
             
               

             
                   
           
             
                
               
          
             
            
             
              
            
            
             
            
           
           
             
            
            
              
            
                
                 
             
         
            
             
               
           
             

           
          
           
             
             
               
               
             
             
            
           
           
             
             
             
               
                  
            
         
     
             
be identied and eliminated quickly. Analysis shows that th   
                 
sufciently quick 400 seconds. False positives are also rar     
               
continuous gameplay before being mistakenly identied as c   
              
             


            
           
           
           
             
          
          
         
           
it becomes possible to compare two resolved messages. By den   
            
      
          
             
              
      
           
            
            
          

Although ofcial reports of cheating in MMOG’s are few, the s   
          
             
            

               
              

             
in 1997 demonstrated signicant problems with respect to th    
                
         
              
               
            
             
  
As a rst hand witness, the result of the high rate of cheating    
           
              
               
            
 
              
             
possible to investigate cheating in MMOG’s by analyzing of   
             
           
            
          
             
 
              
               
                

     
           
          
              
 
Final Fantasy XI is the rst installment in the nal fantasy s     
              
           
             
  
           
             
               
 
            

     
   
   
      
     
              
             
             
              
               
             
           et of enhanced movement

             

              
              
tool was rst introduced. As time continues the number of pla     
        s abandoning this specic cheat.
           
               
               
               
           
                
               
                 
               
of real money traders who estimate that the expected prots o    
         
               
           
               
          il 2007 there was an inux
                
           
                
              
             
or the introduction of new cheater identication code that o   
             
               
             
exact gures on the number of cheaters, there is evidence tha     
               
                  
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            
                
             
              
            
haviour and introduces the denition of cheating that will b    
             
              
              


 
 
             
              
               
           
             
             
               
           
           


             
             
             
             
             
           
             
            

 
              
             
            
        grieng     
             
            
         t a diverse classication of
             
             
            
          
                
          
            
 onch that is of signicance: The mobile guard, which is a meth   
client code remains unmodied via the use of unpredictable downloaded code veriers and
              
              
of mutual verication is of key importance and is closely rel    

               
     for rst person shooter (FPS)games. The cheat works as fol            
and clicks that aim and re at an opponent. Because this cheat i     
               
          
or verication hardware that veries input veracity has bee   
              
                 
           
of cheating often include an attempt to rene the lockstep pr  

 
              
              
           
                
              
           
           
             
            
               
              
            
            
            
                 
             
             
             
             
          
        time which might be difcult to
              
             
         
            
              
strategy (RTS)games as “maphack” and in rst person shooter    
               
adversary moves a secret a mask hides all areas beyond the el     
              
            

 
             
            
                
           rsaries. Cheat verication is
    
             
             
              
cheating players can be identied based on their behaviour p    
                 
             
           


             
                 
              
               
   
            
             
            
           
              
            
             
              
           
             

 
is difcult to apply the proposed cheat elimination schemes     
             
               
       
            
             
           
           
              
          more efcient group commu        f the efciency of several graph
 
             
             
            
            
              
            
              
             
              
             
              
               
             
                
              
             
              


 
             
               
             
                 
though it is applied in a different scenario, they also nd it     
       

 
Cheat Classication
           tial, as a rst step, to deter             
              
     
              
are dened and discussed. It will be shown that the only insta    
                 
          
            
this work builds off of the classication scheme presented i     
             
              
 

  
The task of determining a rigourous denition of cheating is      
present a variety of cheat classications but few present an unambiguous denition of what
           

   
from various cheat classications; however, it is possible to dene a reasonable separation
       
       nted below. The rst cat               
               
becomes evident that to accurately dene cheating behaviou     
and dene game rules and what it means to break them.
            
             
         iour t within the game
              
                 
              

    
               
               
           specic game rules. However,
determining the exact denition of game rules in online game    
       t denes game rules it
becomes possible to produce a rigid denition of cheating. The rst assertion states that
             
              
    : The assertion that game rules are dened by
developer intentions allows for the classication of many n  
as cheats. Unfortunately, such a denition is not without it   
              
          ingly difcult to discern
      

   
                 
                
            
part of the denition of cheating presented herein:
            
           
           
             
            
      
            
         in the popular ghting game
            
gether several moves that are unblockable if the rst attack     
culty of move execution and timing combos became accepted b 
             
 
           
               
          
             
             
         
              
            
          
            
           
           
      

   
            
           
             
           
           
          
             
             
              
             
            
              
              
             
   
             
              
of this thesis, any denition of cheating must include the br   
           
        sication of cheating can
be formulated. Since it is difcult to dene such things as ha    
mathematically theoretic way, a classication of cheating     
            f areas where denitive cheat
identication becomes problematic. The following denition provides a sufciently rigid
classication of cheating and is used throughout this thesi
 
        
               
gurations, respectively, as determined by the      

   
to include all necessary les related with the operation of a   
  
   represent the set of all acceptable modications of     

                
                 
    , hardware congurations in    
ications in               
modications     
                  
                  
    , hardware congurations in  and game modi                  
   and modications              
    with modications     
- Any modication to        is reected by the same modication to
       if and only if for the newly introduced or modied hard     , or game modication   

 
 
 . Deletions will also be reected by client   
 Denition               
      
 
            
                     
                       
         is cheating if it uses a modied version of
       party or modied hardware or software that are
             
this denition exploits are not considered cheating behavi

   
A potential weakness of the above denition is its reliance o     
 , which, due to the limitless number of congurations, might   
            
           
modications are acceptable. Nevertheless, this denitio     
cheat classication and forms a proper basis for this thesis

   
              
           
             
as cheating by the above denition, they can; however, serve     
    
Two types of behaviours are examined below. The rst pertain     
clients and leads to the introduction of the notion of grien    
          
             
           
              
            
   
             
             
            
          
            grieng  
            
              
         

   
An example of grieng would be       
              
             
               
            
Following the above denition of cheating it is evident that grieng is not by
              
           
employ strategies to minimize the prevalence of grieng. Fo   
           
            
            
grieng becomes especially serious. By modifying the behavi   
                
ruin the game experience for others. As a result grieng can s    
for the modication of game code or the installation of prohi   
   
            
             
             
            
           
   
            
            
           
            
         les of bridge it is difcult
           

    
           
               
           
          
           
             
             
that clients have limited opportunity to benet friends; fu     
 

   
            
notion of cheats follow the denition provided in the previo     
              
              
scope of the above denition and are therefore to be examined     
that for discussions of cheating classication in terms of the above denition, it will be
               
   is a common method of cheating, involving the modi              
               
           
interest as the modication of client-side code allows one t    
             
           
              
           
          

    
              
               
         
       ication of client com             
            
         umed that such modi           
            
             
            
 is dened as the purposeful termination of a player’s game co 
              
                
              
interruption on an ad hoc basis. By following the denition of   
above it is evident that such behaviour cannot be classied a   
            
 
Network ooding is when a client overows the game server with game messages i
               
            
               
              
           network ooding is not
game specic; however, its utilization requires the use of t  
party programs, qualifying it as cheating by the above deni
             
            

 
benets of time cheating require the usage of       
              
              
          
             
            
           
            
             
         
          
           
Eavesdropping and message modication are a signicant potential problem if com           
              
             
             


        ity for players to nd and
        lassication attempts to
              
            
             
 

 
  
              
            
efciency of a P2P design while maintaining the security aff    
             
      
             
ned as individual players connected to the game world using      
               
         
              
            
cheat identication.
            
            
             
              
              


  

 
           
               
          
              
            
            
           
             
                
             
           
           
              
             
          
          
           
client base. Proxy assignment is depicted in gure 5.1.
              
depicted in gure 4.1. It ensures that a client’s request mes    
               
request message which may be used for cheat verication. When   
                
                
                
              
        

  
            
             
             
no harmful data is distributed. It is depicted in step 5 of gu     
              
              
             
               
                
           
            

 
Message verication is an important measure in maintaining     
             
              
            
 , represented in gure 4.2, works as follows: during the  
                
               
                
               
        . The rst two result
             
               
                
             
       path-nding   
             

  
          inds of verication results
   
          
   
             
            
     
            
            

             
              

             
            
     

 
            
                
              
             
              
              
             
                  
             

  
            
              
             
               
 

 
             
                
             
                
              
When the server successfully identies an      
               
             
              
                 
               
                
   


             
           
             
         ot provide sufcient evidence
                
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 
             
              
            
              
            
                 
            
              
              
           
             
           
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 
   
           
            
             

 
   
Top left: The reection of a request message to the proxy and r 
            
               
Bottom right: The monitor verication computation and the s    

 
 
             
                 
            
             
            
            
In order to examine the benets and drawbacks of the IRS model i  
             
             
              
            
the many parameters that dene its behaviour.

  
                 
            
              
             

   
             
          
           
           
            
             
          he efcacy of different param      

 
             
             
           
               
  
            
     
          
               
              

           
        
         
                 
              
                   

   
             
mapping. Proxy assignment is depicted in gure 5.1.
   
         
                 
                
            
         
         
            
             
            
             
cessful audits are sent to a monitor for verication. The act      
            
             
              
sufcient in ensuring an effective elimination of cheaters

   
           
            
   

 
In order to emulate an MMOG environment it is essential to de    
          
           
sages and monitor result messages are well-dened.
             
            
            
            
        
          
in the time it takes to be resolved. For example a path nding r  
            
     
            
            
             
        
            
            
             
             
            
       ened by the following:

   
           
            
          
             
            

            
           
The indicator is a ag which can take on the following values:    
              
            
   
          
              
              
              
    
            
               
      
            
          
          
         
             
             
           
         

   
          
                 
           
              
               
            
     
  : In order to aid in the identication of malevolent clients, 
          
           
           
      
              
                 
              
                
            
signicant source of error.
             
               
             
              
 

 
             
             
             

   
            
  
       age accuracy that reects
             
             
             
          
                   
       
 
             
accurate results. They are used in the verication of audits   
        can handle only one verication at a

            
            
returned. Since an error occurring during a path nding oper  
             
               
   
 
   will only cheat for the benet of their friends. Collusion in           
            
         
            
            
            

   
            
          
– Grieng Client            
            
             
           rieng might
            
         
            
         
 
    
            
                
               
              
     
  
  
      
                  

  

 
             
              
            
            
       
             
                
             
             
               

  
           
  
          
              
              
           
             
            
          
    
              
           
                
               
               
            
            
          

 
               
            
              
  
              
           
               
             
   

  
5.2.1
Denitions
             
   
     
   
              
                
             
           denes the total number of clients.
               

    
   
          
     
       
  
              
              
      
              
           
               
             
   
               
as a co-auditor. It is dened as           
               

 

         
                 
             

 


 
  
               
 
                
              
              
      
 

  

   
              
               
    
         
              
               
  
              
behaviour, in which the co-auditor was of type i. This is den 
 

       
               
        

  
             
              
          
                 
 
                  
               
          

  
        
    

 

          rst component repre                
                     
              
                
                  
                
              
               
             
dened as the sum, over all possible co-auditor types, of the      
               
  
    


          



           
              
                  
   
    


          



            
              
            
               

  
 score exponent, dening the total penalty of returning an  
            
    
 

             
    


        
            
       
             

               
             
               
               
 punitive exponent the appropriate negative penalty is den
    
    
 


             
        
 


          



          




 
    
 


             
             
plied model setup dened in the chapter 6 the trust metric’s e      
                

  
               
behaviour is dened per section sec:experiments.
             
        
          
           
                 

           
The resulting unied trust metric is therefore:
 


          


 

 



  
             
              
                
             
               
                  
       
        
              
                  

  
                
               
              
trustworthy clients benet from this increase in expected g    
              
           
              
                
                
               
                     
                  
    
  

         
          
                  
    
  
 
 
           
     
     
 
     
    

         

  
 
        
 
     
     
 
     
    

                 
                
               
                 
       
 
        

 


    


   



 
    



   


 
 
 

 


           

           

 











 
  
   
 
   
  
  
                
          

 


 

 



    
 


   

    


   
          nding the rst terms on both
        

 


     

 


      
 



 
  
  




   

     




     
   

   
    
     


   



   
      
                  
    
        
                
             
                  
             

  
case parameters and equations dened in section 6.1 it is pos    
            
               
              
            
           
              
               
                 
   
          
 
         
 
      

               
   
By solving equation 5.8 at time t with a specic ban threshold,     
               
                
 
 


  
    
  
 

               
              
               
     

  

 



   



       
     

                 
             
               
               
                
           
              
             


            


 
          xhibiting a specic rate or error:
 
   


                 
            
 
   


              
   
              
               
            
   
              
audits. It then nds the chance that a legit client has to exhi     
              

  


        
 


   
       

 
 
                 
             
              
signicant effect to the overall number of false positives,     
             
                 

   
  
  
 
    
      



   

      



 

      

       




 

 

    

  
      
                   
                
               
                
Through slight modication of the above algorithm it become   
           positive up to a specic point
                 
            
             
 
 
            
    

         
new algorithm is dened for determining an individual legit     
                
     nder by the number of legit clients as described above.

 
               
               
               
              
    


         
               
                  
     
          

 


                
tion simplies even further:

  
        
 


               
nd the average number of audits a legit client will be subjec    
   
               
    
   
 


       
  
              
      


        
              
denitions above. It should be noted that game-time does not    
    
 

  

  
      
 
             
                
by the same calculations a single grieng client would last l      
               
           
 

 
 
           
              
these models are investigated in order to clearly dene the s   
          
            
             
           
                

   

          
         
             
              
               
             
              
            

  

 
             
MMOG setting. Their use is justied through investigations     
      
           
           
           
              
             
player who might choose to re a rapid succession of commands
         
            
             
           
             
chosen in order to reect the fact that players will begin to notice a difculty in
             
           
  is dened as the chance that the server opens an audit on an inc
           
   
            
              
              
   


        
Positive audit verication rate          
               
    

6.2. Further Parameter Justication
               
                 
             
      
                
               
           
 
6.2
Further Parameter Justication
          
            
on the correlation of data collected from two sources. The rst derives from path-nding
           
           
               
             
   
Using Mammoth’s path-nding agent on the server was a necess   
             
            
                
          lient that makes path nding
               
              
in each path. The data shows that on average a path nding resu  
             
      
           

       
           
player path-nding request behaviour. Although Mammoth’s path-nding agent was dis             
             
              
based path-nding by counting the number of new path creatio     
                
                 
                 
              
            
               
Orbius if server-computed path-nding were active it would    
              
                
              
solely responsible for path-nding calculations). The path-nding module in Mammoth is
currently based on a simple A* algorithm, and could be signi  
theless, this data provides justication for the range of pa   
          


      
               
              
              
           
each of which tests a specic conguration of parameters. Th   
            

       
               
             
client congurations on cheat removal, message comparison     
               
          
              
   


           
 
 : In order to dene the rates at which certain client types are 
             
  
               
           
            
             
    
             
         
          
           
            
             
            
           
  

       
            
           
           
               
                
          
          
 
             
            
           
            
            
            
            
           
               
            
             
           
           
            
         

    
   is an essential parameter that denes how long dubious clien  
                
              
              

       
               
             
             
             
       
 
              
             
   
 
    
   
   
   
            
           
 
   

        
            
          
            
            
       
          
   
   

       
     
     

               
              
              
are merely scattered but very close in time. The plots in gur    
              
               
           
failures. The rst 3 graphs represent the effects of the diff   
the nal graph depicts the number of false positives for the -     
              
  
It is clear from gure 6.1 that a higher ban threshold results    
                
              
                
               
        

        
            
               
               
cheating rate of hackers, the identication of cheaters becomes more difcult, giving more
             

       
   
   
   
    
      
methods were investigated. The rst trust metric investigated follows a at scoring distribu                
the rst in that it penalizes          
            
           
               
               
             
             

       
          
 
     
  
            
          
 
    
            
   
            
       
      
 

   



   

 

   


   

 
 

              
The rst subsection will deal with      and the nal with
            
trust metric’s efcacy.

       
               
                 
             
           
            
           



 
            
    

   
   
               
gure 6.2. By examining the gures presented it is possible to      
               
           

From gure 6.2 it is also evident that each trust metric seems      
             
             
             
              
  
 

           
              
               
This fact is corroborated by the graphs represented in gure     
             
      
            
            
ization of proxy assignment is apparently a sufcient means      
                

       








        

       
            
             
                 
             
   
              
             
            

Figure 6.3.a)represents the effect of the at trust metric,     
                   
             
              
            
              
              


 


     are caught cheating on their rst resolved message
     
            
             
              
                
            
           
              
                
               
             
               

       








        

       
               
    
The remaining graphs depict more predictable behavior. In    
             
            
             
           
             
               
Effects on Grieng Clients
The graphs in gure 6.4 demonstrates the rate at which     
trust metrics. In all graphs in gure 6.4, like in previous ex     
              
               
                 
            
                
                
            
              
                
messages to legit messages after the cusp of the rst 30 secon    
             
             
 
            



  
               
             
         

       








        

       
               
           nal graph has the fastest
            
    




         
              
               
               




            
             
three non-zero points in gure 6.5.a)at the y value of 0.1. Si      
               
a single experiment reported a false positive at that speci       
          

 
  
        

    
                
                


 
  
             
         
 
   
          


      

 
              
             
rst,            
             
            
   
Experimentation will examine the effects of a specic system conguration’s effect on
         s dened below. By substituting
the variables dened in section 5.2 into equation 5.6 it is po     
                
             

            
scheme and conrm the applied model results. It is shown that    
              
               
      

 
             
    
          
 

  
         
Positive audit verication rate        
         
 
               
           

        
 

 
           
           
             
           
          
              

           
            
    
 : Grieng behaviour remains unchanged from previous experi
           
          

The following denes the client breakdown in both test scena

  
 

   
  



 











   
                
              
                
            
  
             
              
            
           
              
      

     
     
    
 
   

  

  
   
 



 
 
 

   
 

     
 
              
   
 



 
 
 

   
 

     
 
              

                 
             
            
             
the above gures it is difcult to determine the most desirab     
    are quite similar. Play interval is dened as the total lengt  
              
             
               
              
             
             
          

  
   
               
               
             
            
                 
            
                  
             
          
 



 
  
 
  
        

              
             
                 
             
              
             
              
 

  

   
                
ing method that does not sufciently penalize negative beha     
             
        rthy clients. In order to dene a
        
           
               
         d. The rst having exponents of
              
             
                
  

     

   



   

 

   


   

 
 

The data in tables 6.4 and 6.5 conrm that when compared to mal   
                
           
            
            
    



    




 
  
   
 
 






Undened
Undened
 
 
 
     
       
        
   
 
 






Undened
Undened
 
 
 
     
       
        
               
  



      
         


   
              
                 
              

 




 
       
 
       
        

  

Determining the best trust metric candidate is a difcult ta     
    



       
               
            
for grieng clients to exhibit a higher rate of cheating than      
          
                
             
               
    







          
            
             
           
           
  



            
    
Graphs presented in gure 6.6 display the relationship betw   
                
             
              
                
             
                   
                 
             
  
  

   




       



      

  
      
      
           

           





             



    
        
 

  
     
              
  
             
 




            
         nt messages, has the coefcient
         
 , the resulting coefcient is   

 



 
 

  
which simplies to   
   increases, the coefcient becomes less and less, resulting    
            
              
               
                
 
             

  
                
                 
               
                  
             


 
 
            
            
                
             
         erent client congurations, under
            
           
   

    
           
specic environments. It is important, however, to examine    
              
               
             
        gnicantly affect the rates of
          
                 
          

     
7.1.1
The Effects of Different Client Congurations
             
to analyze the effects of different client congurations in     
         mine 3 congurations. The
rst breakdown, examined over 3 batches, is composed of an eq   
              e nal
             
             
      
 
      
   

 
           
     
Client Congurations
         
         
         
         
         

In the three graphs presented in gure 7.1, a familiar cheat e    
                 
            

     
 Conguration: 1
 Conguration: 4
 Conguration: 5
  The Effects on Different Client Congurations

     
               
             
      
The graphs representing the effects on congurations 2 and 3     
similarity to the results for conguration 1. The omitted gr    
             
                
              
       
Graph b)demonstrates the effects of the hybrid model on con     
                 
         
The nal graph presented in gure 7.1 displays a conguratio     
            
              
           
             
mation the banning of cheating clients becomes more difcul      
             
   
Study of false positives in the above conguration also prod  
              
            
       

     
             
             
              
             

     
             
               
             
               
 
 
             
         
 
    
   
   
   
            
           
     
  
         
           

          
       

     
  
  
    
    
       

     

For the graphs presented in gure 7.2, there is no signicant    
            
tives in graphs c)and d)do not show a signicant difference i     
              
          

    
               
          
             
           
              
                
              
       
 
              
           
    
     
              
              
           
             
            
    

     

     
     
    
    
      
The data displayed in gure 7.3 displays interesting result     
              
           o no signicant change in
                  
monitor error, there has been no signicant increase in the n    
               
                

      
               
       

     
                 
              
            
            
            

    
            
                
             
     
 
             
          
             
audit verication results.
  
    
              
       
   

      
   
     
           
              
   

    
        
       
The results presented in gure 7.4 display the effects of the    
                 
               
             
                
             
                 
b)conrms this by demonstrating a sharp decline in the avera      
              

      
                
          

     
            
                
             
                
              
           
               
not have much of a chance, conrming the earlier analysis in s 
 
              
         
            
   
    
             
            
     
   
   
    
   

      
   
   
   
   
    
   
   
   

The graphs presented in gure 7.5 depict the effects of the hy   
                
               
             
               
in the system declines over time. It should be noted that the      
                    
               
     
               
               
           
        
The nal graph, c), demonstrates an interesting trend. It de   
               
                
              

      
    
        
     
       

    
              
             
               
                
               
new, experiencing their rst second in the system and     
                
               
                 
              
This result is further conrmed by a subsequent experiment i     
              
               
              
of cheaters from the system as presented in gure 7.5, it is ap    
           

   
             
The previous experiments examined the efcacy of the hybrid   
              
              
           
              
                 
             
   
             
              

    
           
              
          r; it is dened by taking the
              

               
          The rst experiment de              
            
             
               
               
             
            
10%. The nal experiment analyzes the load introduced by the     
              
           


     
             
                 
           
              
in two gures. The rst pertains to the 10,000 client setting     

 
 

    
     
    
    
    
    
     
    
    

                
             
             
              
                
              
              
             
            
       
Graph a)in both gures represents the server load for the hyb     
            
       ely 28,000 to 32,000 units in gure 7.6 and between 300,000 and 400,000 units in gure 7.7. Th    
              
             
               

    
  
   
 
       

    
  
   
 
       

    
             
           
                
The nal graphs present data pertaining to bandwidth. The gr   
                 
              
number of messages out. From gure 7.6.c), after stabilizat    
               
gure 7.7 depicts values between 125,000 and 175,000. Final    
and c)from both gures it is apparent that by increasing the p     
           
          

 
             
              
            
               
               
             
                
              
           
     

                
            
             

    
    
      
   
     
       

    
            
              
            
            
              
      ’s server load is dened as the
       
         
              
            
                 
              
               
              
               
 
                
              
               
             
           
            
             
               
   
              
               
              
               
            
            

    
 
The data from graphs b)and d)conrm the previous statement.
   
             
               
               
                
                
               
               
             
                 
          d that data reecting the
            

   
As a nal experiment, the overhead of the cheat reduction mec    
            
                
          
              
              
            
              
            

              
               
cheat reduction is active, gure 7.8’s graphs a)and b)are us    
                
            

    
  
    
        
              
               
               
                
            
         
              
           
              
              
               
             
  
           
and 1.35 messages per client per second lower than that of gu    
              
            
signicant server cost and a slight bandwidth cost related t    
            

     
          
      

    
             
              
             
              
 
             
cation through auditing; however, it has high networks cos       
             
         
            
            
             
         
              
               
               
             
             
             
                
          

 
 
            
         benets for servers. There are,
              
              
  
Data provided in chapter 6 supported the hybrid model’s efc     
cost requirements. In order to reconcile the benets of the s    
              
            
             
               
         , in a sense receiving benet
    
          cal use and efcacy in a
             
the actual costs and benets in a realistic setting. The curr   
         

  

 
             
             
       el usage and modied congu             
hybrid model an even more attractive choice. The rst idea di     
        guration, while the second idea
           
      
 
           
           
            
               
                
             
          
             
               
            
             
              
            
            
     

  
 
              
implementation of the current auditing system using a modi  
         
the current communication model it is possible to dene new m  
             
           
modications were made that devise a similar system with imp    
               

            
ure 8.1. The rst step in dening the new model is the eliminat    
              
            
              
                
              
                 

            
               
gure 8.1’s top right panel. It should be noted that the messa      
               
               
                  
             
                
     
In the nal stages,            
                 

  
                  
                  
                
                
                 
                

             
              
                   
                 
               
                
              
                
               
             
            
gure 8.2, the server delivers a copy of the request message t      
              
             
                
              
    
            
           
              
message data whereas the nal message contains a small amoun       
              
              
     

  
     
               
             
             
            
        
In summary, the exibility of the hybrid model allows for man  
tations. The performance of modications can serve to enhan      
            
             
             

  
      
            
future study and examination of modied hybrid model conifg   
             
    

 
            
             
               
             
            
             
          
             
            
accordance to the communication model dened in chapter 4 an   
          
           


  
           
             


 

            
             
              
               
            
              
             
with the scalability and efciency of a P2P architecture.
             
              
             
              
investigation and assurance of unmodied message delivery  
           
             
           
   
            
              
            

             
           
            
            
           
          
             
           
           
             
different parameter congurations were analyzed using the    
            
           
            
               
              
           
  
                
           
             
              
      
          
             
             
               
                
               
              
           


      

    
      

              
             
         
   
               
    
             
         
    
             
         


               
           
          
ing, Articial Intelligence, Networking, and Parallel/Dist  
      
                 
         
          
      
              
           
           
       
              
           
          
     
               
            
         
             
           
           
[14] E. Cronin, B. Filstrup, and S. Jamin. Cheat-proong dead re 
          
       


[15] E. Cronin, B. Filstrup, A. R. Kurc, and S. Jamin. An efcient  
            
          
              
            
         
[17] C. Y. Foo. Redening grief play. In       
    
            
   
            
           
  
  
    




              
         
   
               
          
             

             
           
    


             
        
            
        
[26] M. Lanctot, N. N. M. Sun, and C. Verbrugge. Path-nding fo   
           
         
                 
            
        
      
             
           
           
      
             
            
         
               
         
   
               
          
          
      


            
           
           
            
                
          
           
 
[35] J. Parish. The essential 50, part 32: Street ghter ii. 

          
       

               
            
          

             
           
   
           
           
           
  
           
         


               
           
          
            
   
  
[43] J. Yan and B. Randell. A systematic classication of cheat    
           
           
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