A. Kerberos [1]
This protocol, client has to ask for ticket from
authentication and ticket granting server for destination server
connection. After that, client should send this ticket to target
server. Destination server verify client from received ticket
whether the client is authentic or not. If the user is authentic
then destination server should either client to access computer
resource or reject elsewhere. The problem of Kerberos
protocol is that there has to defined authentication and ticket
granting server. If there are many client’s concurrency
occurred requests then there may be a bottleneck affect
happened. The other problems are timing synchronous
between client and server which should not together matched
if they were located in different time zone area