..
use Digest::MD5 qw(md5 md5_hex md5_base64);
..
# md5 salt
my $salt = "any_salt";

#constructor
sub new {
	my ($class) = @_;
	my $self = $class->SUPER::new();
	$self->{_NAME}     = $_[1];
	$self->{_PASSWORD} = $_[2];
	bless $self, $class and return $self;
}

sub ENCRYPT {
	return "[" . md5_base64( md5_hex( md5( "[" . $salt . $_[0] ) ) ) . "]";
}

...

##</code><code>##

$user->ENCRYPT("test") eq User::ENCRYPT("test")

##</code><code>##

User::ENCRYPT = [pFEzt3UedzYAtjFwAGLDRQ]
$User->ENCRYPT = [TmLr4v17FTUVqcO+Gb2K/Q]