What do you mean protect them ? Are you referring to your storage of altcoins like wallet ? If you are using MyEtherWallet. The best way to protect it is to take care of your private key. Don't allow anyone to have it. As long as your private key is safe and no one knows, your altcoins are safe too. Protect yourself, protect your funds.
You and only you are responsible for your security.
1. Be diligent to keep your private key and password safe. Your private key is sometimes called your mnemonic phrase, keystore file, UTC file, JSON file, wallet file.
2. If you lose your private key or password, no one can recover it.
3. If you enter your private key on a phishing website, you will have all your funds taken.
And if you lose your private key or password, it is gone forever. Don't lose it.
Make a backup of your private key and password. Do NOT just store it on your computer. Print it out on a piece of paper or save it to a USB drive.
Store this paper or USB drive in a different physical location. A backup is not useful if it is destroyed by a fire or flood along with your laptop.
Do not store your private key in Dropbox, Google Drive, or other cloud storage. If that account is compromised, your funds will be stolen.
If you have more than 1-week's worth of pay worth of cryptocurrency, get a hardware wallet. No excuses. It's worth it. I promise.
Reference Sites:
https://myetherwallet.github.io/knowledge-base/getting-started/protecting-yourself-and-your-funds.htmlhttps://www.myetherwallet.com/