my $string = "Four score and seven years ago..."; 
 
print $string, "\n"; 
$string =~ tr/a-zA-Z/n-za-mN-ZA-M/; 
print $string, "\n"; 
$string =~ tr/a-zA-Z/n-za-mN-ZA-M/; 
print $string, "\n";

my $password = 'bedrock'; 
my $salt = 'qN'; #some 'random' two characters 
  
my $encrypted = crypt ($password, $salt); 
  
if ($encrypted eq crypt ($password, $encrypted)) { 
	print "welcome back\n"; 
} else { 
	print "your password does not match\n"; 
}