When setting up a wireless network and router, it's essential to secure it so it's not accessible to anyone within range of your router, such as neighbours and passers-by. To secure a wireless network, wi-fi routers include security and data encryption features, usually in the form of a password or 'key'.

All routers have some form of encryption, but there are two main types: WEP (Wired Equivalent Privacy) and WPA (Wi-fi protected access). Both WEP and WPA use a key (password) to allow only devices with the correct authorisation to access the wireless network. 

WPA is the newer standard. It's stronger than WEP, as it scrambles the encryption key, but you should check before setting up your network that all devices you want to connect to the router are WPA-compatible. WPA2 is the latest WPA standard, and WPA2-PSK (Pre-Shared Key) is designed for small home networks, where you choose a passphrase between 8 and 63 characters long.