<?php
$token = "dige1994";
$signature = $_GET["signature"];
$timestamp = $_GET["timestamp"];
$nonce = $_GET["nonce"];
$echostr = $_GET["echostr"];

$tmpArr = array($token, $timestamp, $nonce);
sort($tmpArr);
$tmpStr = implode( $tmpArr );
$tmpStr = sha1( $tmpStr );

if($tmpStr == $signature ){
    echo $echostr;
}else{
    echo "err";
}
?>

<?php
define("TOKEN", "dige1994"); //TOKEN值
$wechatObj = new wechat();
$wechatObj->valid();
class wechat{
    public function valid() {
        $echoStr = $_GET["echostr"];
        if($this->checkSignature()){
            echo $echoStr;
            exit;
            }
    }
    private function checkSignature() {
        $signature = $_GET["signature"];
        $timestamp = $_GET["timestamp"];
        $nonce = $_GET["nonce"];
        $token = TOKEN;
        $tmpArr = array($token, $timestamp, $nonce);
        sort($tmpArr);
        $tmpStr = implode( $tmpArr );
        $tmpStr = sha1( $tmpStr );
        if( $tmpStr == $signature ) {
            return true;
        } else {
            return false;
        }
    }
}
?>