use MD5 ;
	
my $md5 = new MD5 ;
$md5->reset ;

my $yday = (localtime)[7];

# create certificate / session id
my $certif = $user . $yday .  "do4k.g0" . $ENV{'HTTP_USER_AGENT'}  .  $ENV{'REMOTE_ADDR'} ;

# encrypt certificate
$md5->add($certif);
my $enc_cert = $md5->hexdigest() ;

# set cookie
print "Set-Cookie: SESSION=$enc_cert; path=/\n" ;
print "Set-Cookie: NAME=$user; path=/\n"  ;

# and continue
print "Content-type: text/html\n\n"  ;
print "Your logged In!"  ;

##</code><code>##

#  $session and $user came from cookie
use MD5 ;
	
my $md5 = new MD5 ;
$md5->reset ;

#create ceritficate
my $yday = (localtime)[7];
my $certif = $username . $yday . do4k.g0 . $ENV{'HTTP_USER_AGENT'}  .  $ENV{'REMOTE_ADDR'}  ;

# encrypt Certificate
$md5->add($certif);
my $enc_cert = $md5->hexdigest() ;

#compare
if($enc_cert eq $session) {
   # we're logged in - run script ;
} else {
   # we're not logged in - disp error msg
}


##</code><code>##

print<<"END" ;
Set-Cookie: SESSION=; path=\
Set-Cookie: NAME=; path=\
Content-type: text/html

Your logged out now
END