#!perl
use strict;

package Whatever;

my $password = sub { 'passwd_here' };

sub reveal_pass {
    print "Authorised: ", $password->(), "\n";
}
  
package main;

Whatever::reveal_pass;

print "Unauthorised: ";
print ref $Whatever::password ? $Whatever::password->() : "no access!\n";

__END__
Authorised: passwd_here
Unauthorised: no access!