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Diff for /loncom/lonenc.pm between versions 1.8 and 1.9

version 1.8, 2004/12/17 21:44:19 version 1.9, 2004/12/20 19:26:53
Line 34  use Apache::lonnet(); Line 34  use Apache::lonnet();
 use Apache::File();  use Apache::File();
 use Apache::loncommon;  use Apache::loncommon;
 use Crypt::IDEA;  use Crypt::IDEA;
   use Time::HiRes qw(gettimeofday);
   
 sub handler {  sub handler {
     my $r = shift;      my $r = shift;
Line 83  sub unencrypted { Line 84  sub unencrypted {
   );    );
     }      }
     $ENV{'request.enc'}=1;      $ENV{'request.enc'}=1;
       $decuri=&remove_noise($decuri);
     return substr($decuri,0,$cmdlength);      return substr($decuri,0,$cmdlength);
 }  }
   
   # add a randomish character after every 4th caharacter
   sub add_noise {
       my ($uri)=@_;
       my @noise=split(/(.)/,(&gettimeofday())[1]);
       my $noisy;
       my $i;
       foreach my $chunk (split(/(....)/,$uri)) {
    $noisy.=$chunk;
    $noisy.=$noise[($i++)%(scalar@noise)];
       }
       return $noisy;
   }
   
   # remove every fifth character
   sub remove_noise {
       my ($uri)=@_;
       my $clean;
       foreach my $chunk (split(/(....)./,$uri)) { $clean.=$chunk; }
       return $clean;
   }
   
 sub encrypted {  sub encrypted {
     my $uri=shift;      my $uri=shift;
     if ($ENV{'request.role.adv'}) { return($uri); }      if ($ENV{'request.role.adv'}) { return($uri); }
Line 94  sub encrypted { Line 117  sub encrypted {
  return $uri;   return $uri;
     }      }
     my $cmdlength=length($uri);      my $cmdlength=length($uri);
     $uri.='00000000';      # add noise before enc so that that same url's look different
       $uri=&add_noise($uri);
       my $noiselength=length($uri);
       $uri.=time;
     my $encuri='';      my $encuri='';
     my $cipher=new IDEA $seed;      my $cipher=new IDEA $seed;
     for (my $encidx=0;$encidx<=$cmdlength;$encidx+=8) {      for (my $encidx=0;$encidx<=$noiselength;$encidx+=8) {
  $encuri.=unpack("H16",   $encuri.=unpack("H16",
  $cipher->encrypt(substr($uri,$encidx,8)));   $cipher->encrypt(substr($uri,$encidx,8)));
     }      }
Removed from v.1.8  
changed lines
  Added in v.1.9

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