Name of the key used for authentication; this name is mutually known to the security originator and the security recipient, is unique for this relationship, and is intended to allow the changing of the key from time to time Note: The special key name "0123456789ABCDEF" is reserved for the hexadecimal value 0123456789ABCDEF (i.e. a fixed non-secret value) to provide a well-known value for data integrity testing only)