我们知道php的cookie是明文方式记录在本机上，有些数据要需要有点保密需求，所以写了这个class。

其中加密算法修改于 网站上流传的 xxtea算法.

代码如下

1.class.xxtea.php

andot@ujn.edu.cn>
* Version:      1.5
* LastModified: Dec 5, 2006
* This library is free. You can redistribute it and/or modify it.
* max修改于2008.08.08 maxtank@qq.com
*/

class xxtea{

private $key1 = 'AmPu$this1';
private function long2str($v, $w) {
   $len = count($v);
   $n = ($len - 1) << 2;
   if ($w) {
    $m = $v[$len - 1];
    if (($m < $n - 3) || ($m > $n)) return false;
    $n = $m;
   }
   $s = array();
   for ($i = 0; $i < $len; $i++) {
    $s[$i] = pack("V", $v[$i]);
   }
   if ($w) {
    return substr(join('', $s), 0, $n);
   }
   else {
    return join('', $s);
   }
}

private function str2long($s, $w) {
   $v = unpack("V*", $s. str_repeat("\0", (4 - strlen($s) % 4) & 3));
   $v = array_values($v);
   if ($w) {
    $v[count($v)] = strlen($s);
   }
   return $v;
}

private function int32($n) {
   while ($n >= 2147483648) $n -= 4294967296;
   while ($n <= -2147483649) $n += 4294967296;
   return (int)$n;
}

protected function xxtea_encrypt($str, $key) {
   if ($str == "") {
    return "";
   }
   $v = $this->str2long($str, true);
   $k = $this->str2long($key, false);
   if (count($k) < 4) {
    for ($i = count($k); $i < 4; $i++) {
     $k[$i] = 0;
    }
   }
   $n = count($v) - 1;

   $z = $v[$n];
   $y = $v[0];
   $delta = 0x9E3779B9;
   $q = floor(6 + 52 / ($n + 1));
   $sum = 0;
   while (0 < $q--) {
    $sum = $this->int32($sum + $delta);
    $e = $sum >> 2 & 3;
    for ($p = 0; $p < $n; $p++) {
     $y = $v[$p + 1];
     $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
     $z = $v[$p] = $this->int32($v[$p] + $mx);
    }
    $y = $v[0];
    $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
    $z = $v[$n] = $this->int32($v[$n] + $mx);
   }
   return $this->long2str($v, false);
}

protected function xxtea_decrypt($str, $key) {
   if ($str == "") {
    return "";
   }
   $v = $this->str2long($str, false);
   $k = $this->str2long($key, false);
   if (count($k) < 4) {
    for ($i = count($k); $i < 4; $i++) {
     $k[$i] = 0;
    }
   }
   $n = count($v) - 1;

   $z = $v[$n];
   $y = $v[0];
   $delta = 0x9E3779B9;
   $q = floor(6 + 52 / ($n + 1));
   $sum = $this->int32($q * $delta);
   while ($sum != 0) {
    $e = $sum >> 2 & 3;
    for ($p = $n; $p > 0; $p--) {
     $z = $v[$p - 1];
     $mx = $this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
     $y = $v[$p] = $this->int32($v[$p] - $mx);
    }
    $z = $v[$n];
    $mx =$this->int32((($z >> 5 & 0x07ffffff) ^ $y << 2) + (($y >> 3 & 0x1fffffff) ^ $z << 4)) ^ $this->int32(($sum ^ $y) + ($k[$p & 3 ^ $e] ^ $z));
    $y = $v[0] = $this->int32($v[0] - $mx);
    $sum = $this->int32($sum - $delta);
   }
   return $this->long2str($v, true);
}

//转化为16进制
protected function stringToHex ($s) {
   $r = "0x";
   $hexes = array ("0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f");
   for ($i=0; $i> 4)] . $hexes [(ord($s{$i}) & 0xf)]);}
   return $r;
}

//16进抽转化为代码
protected function hexToString ($h) {
   $r = "";
   for ($i= (substr($h, 0, 2)=="0x")?2:0; $istringToHex($this->xxtea_encrypt($str,$this->key1));
}

//解密
public function decrypt($str){
   return $this->xxtea_decrypt($this->hexToString($str),$this->key1);
}

}
?>

2. class.safe.cookie.php

itime = 60*60*24*30; //30天过期
}
//设置安全cookie(名称,值)
public function set_cookie($cn,$cv){
   $cv = parent::encrypt($cv); //调用父类的方法
   setcookie($cn, $cv, time() + $this->itime);
}
//读取cookie(名称)
public function get_cookie($cn){
   return parent::decrypt($_COOKIE[$cn]);
}
//删除cookie(名称)
public function del_cookie($cn){
   setcookie($cn,"",time()-3600);
}
//删除所有cookie(名称)
public function del_all_cookie(){
   foreach ($_COOKIE as $name => $value) {
     setcookie($name,"",time()-3600);
   }
}
}

/*
$n = new SafeCookie();
print_r($_COOKIE);
$n->set_cookie("abc","中国人啊56611");
$n->set_cookie("ab11c","中国");
$n->del_cookie("ab11c");
$n->del_all_cookie();
print_r($_COOKIE);
*/

?>