php 加密解密

function lock($data) {
    $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-=+";
    $key = 'z123j456s789';
    if($data['type'] == 'encode') {
        $nh = rand(0,64);
        $ch = $chars[$nh];
        $mdKey = md5($key.$ch);
        $mdKey = substr($mdKey,$nh%8, $nh%8+7);
        $txt = base64_encode($data['param']);
        $tmp = '';
        $i=0;$j=0;$k = 0;
        for ($i=0; $i<strlen($txt); $i++) {
            $k = $k == strlen($mdKey) ? 0 : $k;
            $j = ($nh+strpos($chars,$txt[$i])+ord($mdKey[$k++]))%64;
            $tmp .= $chars[$j];
        }
        return urlencode($ch.$tmp);
    }else if($data['type'] == 'decode') {
        $txt = urldecode($data['param']);
        $ch = $txt[0];
        $nh = strpos($chars,$ch);
        $mdKey = md5($key.$ch);
        $mdKey = substr($mdKey,$nh%8, $nh%8+7);
        $txt = substr($txt,1);
        $tmp = '';
        $i=0;$j=0; $k = 0;
        for ($i=0; $i<strlen($txt); $i++) {
            $k = $k == strlen($mdKey) ? 0 : $k;
            $j = strpos($chars,$txt[$i])-$nh - ord($mdKey[$k++]);
            while ($j<0) $j+=64;
            $tmp .= $chars[$j];
        }
        return base64_decode($tmp);
    }
}

//加密
$encode = lock(array('param' => '测测哈哈', 'type' => 'encode'));
echo $encode.'<br/>';
//解密
echo lock(array('param' => $encode, 'type' => 'decode'));

　　测试结果：