function checkSignature($token) {
$signature = !empty($_GET["signature"]) ? $_GET["signature"] : null;
$timestamp = !empty($_GET["timestamp"]) ? $_GET["timestamp"] : null;
$nonce = !empty($_GET["nonce"]) ? $_GET["nonce"] : null;
$tmpArr = array($token, $timestamp, $nonce);
sort($tmpArr, SORT_STRING);
$tmpStr = implode($tmpArr);
return sha1($tmpStr) == $signature;
}
// 微信公众后台填写的Token
$token = 'itsource';
// 如果验证正确，则返回参数echostr的内容，否则终止执行
if(checkSignature($token)) {
echo $_GET['echostr'];
}
exit();
