/*     efdtt.c     Author:  Charles M. Hannum <root@ihack.net>             */
/*                                                                         */
/*     Thanks to Phil Carmody <fatphil@asdf.org> for additional tweaks.    */
/*                                                                         */
/*     DVD-logo shaped version by Alex Bowley <alex@hyperspeed.org>        */
/*                                                                         */
/*     Usage is:  cat title-key scrambled.vob | efdtt >clear.vob           */


#define m(i)(x[i]^s[i+84])<<

                   unsigned char x[5]      ,y,s[2048];main(  
                   n){for( read(0,x,5     );read(0,s ,n=2048  
                            ); write(1   ,s,n)         )if(s 
                  [y=s      [13]%8+20]  /16%4  ==1      ){int 
                  i=m(      1)17  ^256 +m(0)   8,k      =m(2) 
                  0,j=      m(4)   17^ m(3)   9^k*     2-k%8 
                  ^8,a     =0,c    =26;for   (s[y]    -=16;  
                 --c;j  *=2)a=     a*2^i&    1,i=i /2^j&1   
                 <<24;for(j=        127;     ++j<n;c=c>     
                                    y)                      
                                    c                       
                                             
                           +=y=i^i/8^i>>4^i>>12,              
                  i=i>>8^y<<17,a^=a>>14,y=a^a*8^a<<6,a=a     
                >>8^y<<9,k=s[j],k         ="7Wo~'G_\216"[k   
                 &7]+2^"cr3sfw6v;*k+>/n."[k>>4]*2^k*257/
                       8,s[j]=k^(k&k*2&34)*6^c+~y       
                                  ;}}