An information packet used to securely pass the identity of a user to a server or service. A ticket is good for only a single client and a particular service on a specific server. It contains the principal name of the service, the principal name of the user, the IP address of the user's host, a timestamp, and a value to define the lifetime of the ticket. A ticket is created with a random session key to be used by the client and the service. Once a ticket has been created, it can be reused until the ticket expires. A ticket only serves to authenticate a client when presented along with a fresh authenticator. See also authenticator, credential, service, session key.