JFIFxxC      C  " }!1AQa"q2#BR$3br %&'()*456789:CDEFGHIJSTUVWXYZcdefghijstuvwxyz w!1AQaq"2B #3RbrgetSecretKey(); $dataToSign = implode(':', $params); $mac = hash_hmac('sha256', $dataToSign, $secretKey, true); return bin2hex($mac); }