A keyfile (or key-file) is a file on a computer which contains encryption or license keys.
A common use is web server software running secure socket layer (SSL) protocols.
By this method keys can be updated without recompiling software or rebooting the server.
Some applications use a keyfile to hold licensing information, which is periodically reviewed to ensure currency and compliance.
Other applications allow users to merge multiple service-specific security settings into a single common store (for example, Apple Computer's Keychain in later Mac OS X versions, GNOME Keyring and KWallet in the GNOME and KDE environments in Linux, respectively).