<?php

    $signature = $_GET["signature"];

    $timestamp = $_GET["timestamp"];

    $nonce     = $_GET["nonce"];

    $echostr   = $_GET["echostr"];

​

    $token = '后台填写的Token';

    $tmpArr = array($token, $timestamp, $nonce);

    sort($tmpArr, SORT_STRING);

    $tmpStr = implode($tmpArr);

    $tmpStr = sha1($tmpStr);

​

    if ($tmpStr == $signature ) {

        echo $echostr;

    } else {

        echo 'FAIL';

    }