Generate Signature

public function index(){
        $HTTPMethod = 'GET';
        $RelativeUrl = '/banking/v3/corporates/h2hauto008/accounts/0613006572/statements?EndDate=2020-01-21&StartDate=2020-01-15';
        $AccessToken = $_GET['token'];
        $Timestamp = '2020-01-23T13:11:00.000+07:00';
        $RequestBody = '';
        $StringToSign =
            $HTTPMethod  .":" .
            $RelativeUrl .":" .
            $AccessToken .":" .
            strtolower(hash('sha256',$RequestBody)) .":" .
            $Timestamp;
        $hash = hash_hmac ('sha256', $StringToSign, '5e636b16-df7f-4a53-afbe-497e6fe07edc');
        return array(
            'hash_hmac' => $hash,
            'Stringtosign' => $StringToSign
        );
}