How to store php user information cache

<?php
session_start();
//假设用户登录成功获得了以下用户数据
$userinfo = array(
    &#39;uid&#39;  => 10000,
    &#39;name&#39; => &#39;spark&#39;,
    &#39;email&#39; => &#39;spark@imooc.com&#39;,
    &#39;sex&#39;  => &#39;man&#39;,
    &#39;age&#39;  => &#39;18&#39;
);
header("content-type:text/html; charset=utf-8");


/* 将用户信息保存到session中 */
$_SESSION[&#39;uid&#39;] = $userinfo[&#39;uid&#39;];
$_SESSION[&#39;name&#39;] = $userinfo[&#39;name&#39;];
$_SESSION[&#39;userinfo&#39;] = $userinfo;


//* 将用户数据保存到cookie中的一个简单方法 */
$secureKey = &#39;334246&#39;; //加密密钥
$str = serialize($userinfo); //将用户信息序列化
//用户信息加密前
$str = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($secureKey), $str, MCRYPT_MODE_ECB));
//用户信息加密后
//将加密后的用户数据存储到cookie中
setcookie(&#39;userinfo&#39;, $str);


//当需要使用时进行解密
$str = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($secureKey), base64_decode($str), MCRYPT_MODE_ECB);
$uinfo = unserialize($str);
echo "解密后的用户信息：<br>";
print_r($uinfo);