My app just has a in app purchase for full license. It has no subscriptions, no downloads of items from any server. The license purchase is performed just one time and accounts are not managed so just the Google account is relevant. The Google account is the user. I am pointing all this out because I have strongly protected the private key and the sku name and deem it is enough for my app.
Is strongly protecting the private key and the sku name enough for an app like mine? I think it is enough: no developer payload (no accounts) or nonce (no replay attacks) are needed. Am I right or wrong?