I'm sorry for my lack of technical understanding, but if there were a back door in btc.

1. Could this be fixed easily before it could be used in a way to hurt btc? i.e do you need a super computer to utilize this back door?
2. would this same issue be there in all alts that were essentially cloned from btc code or does using a different algo or POS help to nullify this backdoor?

I am not sure if you thread was deleted since you didn't receive a PM about it. Does one receive a personal message when a thread is moved?