The locking system is a system that is used to prove the identity of the users of such a system, the disadvantage is that if a malicious user can intercept messages that are received through a channel that is not secure.
Lock-in system is used for the authentication of the user. The disadvantage of such a system is. If a compromise can capture information that is transported over insecure channels. Guests can make use of the user to access the system.
System log is the system used for the authentication of the user. The disadvantage of such a system. If the malefactors can trap information which is transmitted channel is not safe.