#!/usr/bin/perl -w
 
$key=0;        #Initialize variables. 
$updown=0;
$i=0;
@arrdone=(0,0,0,0,0,0,0,0);
 
print "Enter passphrase: ";
 
$phrase=<STDIN>;
chomp $phrase;
 
@letters = split //,$phrase;
 
foreach $CHAR (@letters) {  #Use phrase to create random seed
  $newbits=ord($CHAR);
  $modulo = $newbits % 10;
  if ($updown == 0) {
    if ($key < 0){$key*=-1;}
    $key=$key*($modulo+1);
    $key+=$newbits;
    if ($key>4294967294){$updown=1;}
  }
  if ($updown == 1) {
    $key=$key/($modulo+1)-($key%($modulo+1)/($modulo+1));
    $key-=$newbits;
    if ($key<0){$updown=0;}
  }
}
 
srand $key;
 
while(<STDIN>) {
 chomp;
 @inputchars = split //;
 foreach $CHAR (@inputchars){
 $charnum=ord($CHAR);
 $oldt=$charnum;
 
 for (0..8) {      #Translate the input char into binary
  $t = $charnum % (2**$_);
  if($t==$oldt) {
   $binarr[8-$_]=0;
  }else {$binarr[8-$_]=1;}
  $oldt=$t;
 }  
 
  while ($i<8) {   #Assemble the key bit vector.
    $randout=rand(8)%8;
    if ($arrdone[$randout]==0) {
    $shifter[$i]=$randout;
    $arrdone[$randout]=1;
    $i++;
    }
  }
 
  for(0..7) {      #Assemble the scrambled bit vector.
    if ($binarr[$_]==1) {
    $outchar[$shifter[$_]] = 1;
    }
    else {$outchar[$shifter[$_]] =0;}
  }
 
  for(0..7) {     #Rejoin the new bits to an ord
    if ($outchar[$_]==1) {
    $sum+=2**(7-$_);
    }
  }
 
  $och= chr($sum);    #Print the char.
  print $och;
 
  $i=0;     #Reset variables
  $sum=0;
   for(0..7){
    $outchar[$_]=0;
    $arrdone[$_]=0;
    $shifter[$_]=0;
   }
  }
 }
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