Kerberos - Invented by MIT, this protocol has been evolving in the Unix world for over a decade and has become a standard in Windows operating systems. Kerberos is a network authentication protocol which utilizes symmetric cryptography to provide authentication for client-server applications. The core of a Kerberos architecture is the KDC (Key Distribution Server) that serves as the trusted third party and is responsible for storing authentication information and using it to securely authenticate users and services. In order for this security method to work, it is paramount that the KDC is available and secure. The clocks of all hosts involved must be synchronized as well. For more information read Kerberos Security.
Keyboard - Keyboards are input devices for typing that connect to the motherboard. Most desktop keyboards are of the 101/102 key variety while notebook computers use smaller that usually have around 84 keys. Older AT keyboards used a 5 pin DIN connection while newer standards use a 6 pin mini DIN connector, USB, or wireless connection.
KVM Switch - A Keyboard, Video, Mouse (KVM) Switch is a device that allows multiple computers to share 1 keyboard, video monitor, and mouse. A KVM switch allows the user to interact only with one computer at a time, but a series of key strokes or other method can be used to switch computers.