What is the best methods to protect altcoin from hacker?
take care of your private key, passwords and dont click any suspicious link that has been sent to you through pm, shared on any social media sites, etc. the only reason why hackers have the access on your account is because they successfully get your key.
Exactly he's right, you must keep your private key or ip address so that hackers or scammers can't have those. You must read every detail given before you click or enter that link that has been sent to you, this way you can avoid hackers to have your account and it it will save your altcoin.