use CGI::Session;
use Data::Dumper;

my %hash  = ( foo => 1, bar => 2 );
my $session = new CGI::Session("driver:File", undef, {Directory=>'/temp'});
$session->param(-name=>'hash', -value=>\%hash);
my $hash_ref = $session->param('hash');
print Dumper $hash_ref,