A WEP key is a security passcode for Wi-Fi devices that is used to authenticate a connection to a wireless network. WEP stands for Wired Equivalent Privacy, which is a Wi-Fi wireless network security standard. It was introduced in 1999 and was widely used at one time, recognizable by its key of 10 or 26 hexadecimal digits (40 or 104 bits). WEP keys are used for encrypting data frames and can be either 64-bit or 128-bit in length. Most routers offer two types of WPA2 encryption, called WPA2-Personal and WPA2-Enterprise, which are more secure than WEP.

If you need to find your WEP key, you can access your routers configuration interface using an internet browser. The WEP key is usually found in the "security" tab of your wireless router settings. Once you know the WEP key, you will need to enter it when prompted to connect to the wireless network.