A network security key is a password-based encryption setting used on wireless networks. It is typically a hexadecimal number varying in length between 128 and 256 bits long depending on what type of encryption method is used.
A network administrator sets up the network security key on the wireless router. Two common types of encryption are WEP, or wired equivalent privacy, and WPA, also known as Wi-Fi protected access. To authenticate with the network, a user needs to match the protocols and password values on his device to those already set on the router. Devices can remember the network security key so they can re-connect with the network seamlessly.