onetimepadxor

Encrypt:

#!/usr/bin/perl


if(@ARGV == 0)
{
        print "Usage: $0 <num recipients>\n";
        print "Creates a base 64 encoded set of encrypted data which when xor'ed together, produces the secret text\n";
        exit 1;
}

my $num_rec = shift @ARGV;

print "Enter secret: \n";

my $secret = <STDIN>;

my @secret = map { ord($_) } (split(//,$secret));

my @p1;
my @p2 = @secret;

while($num_rec > 1)
{
   @p1 = @p2;
   @p2 = gen_random(scalar @p1);
   my @xor = xorit(\@p1,\@p2);
   print encode(@xor)."\n";
   $num_rec --;
}

print encode(@p2)."\n";

sub gen_random
{
  my $l  = shift @_;

  my @a;

  while(--$l >= 0) { push @a, int(rand(256)); }

  @a;
}

sub xorit
{
  my ($p1, $p2) = @_;
  my @a;

  for(my $i = 0; $i < @$p1; $i++)
  {
      push @a, $p1->[$i] ^ $p2->[$i];
  }

  return @a;
}


sub encode
{
    join(" ",@_);
}

------------
Decrypt:

#!/usr/bin/perl

print "Enter code(s) and a blank line to stop\n";

while(1)
{
    my $d = <STDIN>;
    if($d =~ /^\s*$/s)
    {
        last;
    }

    $i = 0;

    while($d =~ /(\d+)/g)
    {
        $v[$i] = (int($v[$i]) ^ int($1));
        $i++;
    }
}

print "\nAns\n";
print join(" ", @v);
print "\n";
print map { if($_ > ord(' ') && $_ < ord('~') || $_ == ord("\n")) {chr($_)} else { '.';} } @v;
print "\n";