php接口加密怎么做

<?php

$xpp_key = "xxx";

//接收参数param,将结果解析json得到参数数组
$param = json_decode($_POST['param'] , true);

//取出sign,去掉参数数组中的sign
$client_sign = $param['sign'];
unset($param['sign']);

//将参数数组key值按照自然排序从大到小排序
krsort($param);

//将排序后的参数数组按照key=val&key=val的形式组成字符串，将字符串与XPP_KEY连接，用md5加密一次(32位小写)，得到sign
$sb = '';
foreach($param as $key=>$val){
$sb .= $key . '=' . $val . '&';
}
$sb .= $xpp_key;
$server_sign = md5($sb);

//将sign与客户端传过来的sign进行比对,如不一样则可能是中途被篡改参数，服务器拒绝此次请求
if($server_sign !== $client_sign){
echo json_encode(array('code'=>'invalid request'));
exit;
}

//将sign与session中的sign对比，如果一样，则为重复提交，服务器拒绝此次请求
if($server_sign == $_SESSION['last_sign']){
echo json_encode(array('code'=>'Repeated requests'));
exit();
}

//此次的sign存入session
$_SESSION['last_sign'] = $server_sign;

//执行路由cmd(base64解析后),将参数带到该方法中
$cmd = base64_decode($param['cmd']);
list($__controller,$__action) = explode('-' , $cmd);

// 设置请求参数
unset($param['cmd']);
unset($param['timestamp']);
foreach($param as $key => $val){
$_REQUEST[$key] = $val;
}