K

KDC (Key Distribution Server)

A server that maintains a list of user principles for a Kerberos authentication system.

Kerberos

Authentication system based on a unique key, or ticket. Allows encrypted information to be transferred between two parties with valid assigned tickets.

kernel

Also known as a microkernel. The kernel is the underlying core of an operating system.

kernel extension

Also known as KEXT. A kernel extension is a type of loadable bundle that low-level system routines recognize and load into the kernel environment. KEXT bundles have a file extension of .kext.

kernel panic

A system error that terminates core system processes, requiring a restart. It occurs when the kernel receives an instruction that is in an unexpected format or that it fails to handle properly.

keychain

Tool in Mac OS X that stores passwords and user identifications for applications, servers, and other resources, in an encrypted database.