Definition: In computer networking, a passphrase is one or a few small words chosen by an administrator for use as a security setting. Passphrases are designed to make network security settings easier to remember.

Some Wi-Fi home networking equipment utilizes passphrases to generate static encryption keys. Rather than create the long hexadecimal numbers required by protocols like WPA, an administrator may instead enter a passphrase into the setup screens of wireless routers and network adapters.

That setup software then automatically sets the appropriate key based on the passphrase provided.

Note that some sources use the terms "passphrase" and "key" interchangeably.

Wi-Fi passphrases can simplify wireless network setup. Because passphrases are easy to remember, administrators are less likely to enter mismatched security settings on any of their devices. However, not all Wi-Fi gear supports passphrases. In addition, they normally cannot be used on a network when mixing equipment from different manufacturers, as each manufacturer generally employs different algorithms for generating keys from passphrases.