一段加密解密函数

<?

$key = "lanhuizi&cidy=happy";

function keyED($txt,$encrypt_key)

{

$encrypt_key = md5($encrypt_key);

$ctr=0;

$tmp = "";

for ($i=0;$i<strlen($txt);$i++)

{

if ($ctr==strlen($encrypt_key)) $ctr=0;

$tmp.= substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1);

$ctr++;

}

return $tmp;

}

function encrypt($txt,$key)

{

srand((double)microtime()*1000000);

$encrypt_key = md5(rand(0,32000));

$ctr=0;

$tmp = "";

for ($i=0;$i<strlen($txt);$i++)

{

if ($ctr==strlen($encrypt_key)) $ctr=0;

$tmp.= substr($encrypt_key,$ctr,1) .

(substr($txt,$i,1) ^ substr($encrypt_key,$ctr,1));

$ctr++;

}

return keyED($tmp,$key);

}

function decrypt($txt,$key)

{

$txt = keyED($txt,$key);

$tmp = "";

for ($i=0;$i<strlen($txt);$i++)

{

$md5 = substr($txt,$i,1);

$i++;

$tmp.= (substr($txt,$i,1) ^ $md5);

}

return $tmp;

}

?>