package Foo;
use strict;
use Hash::Util qw( lock_keys );

my @attrs = qw( name alias race );

sub new {
    my $class = shift;
    my %args = @_;

    my $self = bless {}, $class;
    lock_keys(%$self, @attrs);

    foreach my $k ( @attrs ) {
        if ( exists $args{$k} ) {
            $self->{$k} = $args{$k};
        }
    }
    return $self;
}

package main;

my $c = Foo->new(name => 'Aragorn', alias => 'Strider', race => 'Human');
print "name: $c->{name}\n"; 
print "job:  $c->{job}\n";

##</code><code>##

$ perl test.pl 
name: Aragorn
Attempt to access disallowed key 'job' in a restricted hash at test.pl line 26.