Okay kiddo, imagine you have a secret password that you share with someone you trust, let's say your best friend. This secret password is called a "pre-shared key". You both use this password to protect your things like toys or snacks that you keep in your secret hideouts.
Now, there are some things that are really important that you need to keep secret or safe on your computer or phone, like your pictures or messages. That's where the pre-shared key comes in!
When you set up something on your computer or phone that needs to be kept secret, like a Wi-Fi network or a VPN connection, you can use a pre-shared key. This pre-shared key is like a secret password that only you and the people you choose can use to access that secret thing on your computer or phone.
So, when you want to connect to that Wi-Fi network or VPN, you need to enter the pre-shared key. This helps to make sure that only the people you trust can access that secret thing, kind of like how only you and your best friend can access your secret hideout snacks!
Overall, a pre-shared key is a secret password that you share with trusted people to help keep secret things on your computer or phone safe and secure.