X-LINE-Authorization をPHPで

$secret = 'channel_secret';
$nonce = (new DateTime())->getTimestamp();
$uri = '/v3/payments/request';
$body = json_encode($postData);

$message = $secret . $uri . $body . $nonce;
$hash = hash_hmac('sha256', $message, $secret, true);

return base64_encode($hash);