Have a look at the documentation for crypt. It even specifies a way to do what you are asking:

$pwd = (getpwuid($<))[1];

                   system "stty -echo";
                   print "Password: ";
                   chomp($word = <STDIN>);
                   print "\n";
                   system "stty echo";

                   if (crypt($word, $pwd) ne $pwd) {
                       die "Sorry...\n";
                   } else {
                       print "ok\n";
                   }
[download]

This was lifted straight from perldoc -f crypt.

CU
Robartes-