想要简单一点的可以用session，但session是创建会话，也会创建文件，这样文件会越来越多，会有些影响，所以用cookie会更好一点！

<?php
/**
 * cookie加密登录与验证
 * @param array $userInfo 用户信息
 * @param bool $validate 是否为验证或者填入token值验证，默认为false
 * @param int $expiresTime 过期时间，默认为1天
 * @param string $tag token标签，默认为zz_token
 * @return bool|string
 */
function zz_login($userInfo, $validate = false, $expiresTime = 1, $tag = 'zz_token')
{
    $salt = zz_salt();
    $host = $_SERVER['HTTP_HOST'];
    if (!$salt) {
        return false;
    }
    if (!$validate) {
        try {
            $expiresTime = time() + 3600 * 24 * $expiresTime;
            $token = base64_encode(json_encode(['userInfo' => $userInfo, 'domain' => $host, 'expiresTime' => $expiresTime, 'code' => md5(json_encode($userInfo) . $host . $expiresTime . $salt)]));
            setcookie($tag, $token, $expiresTime, '/');
            return $token;
        } catch (Exception $e) {
            return false;
        }
    } else {
        if($validate === true){
            if (empty($_COOKIE[$tag])) {
                return false;
            }
            $arr = json_decode(base64_decode($_COOKIE[$tag]), true);
        }else{
            $arr = json_decode(base64_decode($validate), true);
        }
        if (empty($arr['userInfo']) || empty($arr['domain']) || $arr['domain'] != $host || empty($arr['code']) || empty($arr['expiresTime']) || $arr['expiresTime'] <= time()) {
            return false;
        }
        return $arr['code'] === md5(json_encode($arr['userInfo']) . $host . $arr['expiresTime'] . $salt);
    }
    return true;
}

/**
 * 生成安全码
 * @return string
 */
function zz_salt()
{
    $root = $_SERVER['DOCUMENT_ROOT'];
    $file = $root.'/salt.php';
    if(is_file($file)){
        include($file);
        if(empty($salt) || empty($saltRoot) || $saltRoot != $root){
            $salt = rand_str(20,true);
            file_put_contents($file,"<?php \r\n\$salt = '{$salt}';\r\n\$saltRoot = '{$root}';");
        }
    }else{
        $salt = rand_str(20,true);
        file_put_contents($file,"<?php \r\n\$salt = '{$salt}';\r\n\$saltRoot = '{$root}';");
    }
    return $salt;
}

/**
 * 生成随机字符串
 * @param int $num 字符串位数，默认为6
 * @param bool $special 使用特殊字符，默认为false
 * @return string
 */ 
function rand_str($num = 6,$special = false)
{
    $str = 'abcedfghjkmnpqrstuvwxyzABCEDFGHJKMNPQRSTUVWXYZ0123456789';
    if($special){
        $str .= '!@#$%^&*';
    }
    return substr(str_shuffle($str), 0, $num);
}

// 登录
$userInfo = ['id' => 1,'username' => 'admin'];
zz_login($userInfo);

// 验证
if(zz_login('',true)){
    echo '登录';
}else{
    echo '未登录';
}

// 获取用户信息
$arr = json_decode(base64_decode($_COOKIE['zz_token']),true);
print_r($arr['userInfo']);