Yixin php verification interface

Yixin verification interface under php

$signature = $_GET['signature'];
$timestamp = $_GET['timestamp'];
$nonce = $_GET['nonce'];
$token="1LYURrl3b89L";//Yes Change and copy to Yixin token

//Combination
$signatureArray = array($token, $timestamp, $nonce);
//Dictionary sort
sort($signatureArray);
//sha1 encryption and verification
if (sha1(implode($signatureArray)) == $signature){
echo $_GET['echostr'];
}