//加密算法
function encode($string = '', $skey = 'cxphp') 
{
     $strArr = str_split(base64_encode($string));
     $strCount = count($strArr);
     foreach (str_split($skey) as $key => $value)
        $key < $strCount && $strArr[$key].=$value;
     return str_replace(array('=', '+', '/'), array('O0O0O', 'o000o', 'oo00o'), join('', $strArr));
}
//解密算法
function decode($string = '', $skey = 'cxphp') 
{
     $strArr = str_split(str_replace(array('O0O0O', 'o000o', 'oo00o'), array('=', '+', '/'), $string), 2);
     $strCount = count($strArr);
     foreach (str_split($skey) as $key => $value)
         $key <= $strCount  && isset($strArr[$key]) && $strArr[$key][1] === $value && $strArr[$key] = $strArr[$key][0];
     return base64_decode(join('', $strArr));
}