Kerberos is a security system that allows secure communication between computers by preventing third person to steal information sent across wires. The Kerberos system guards electronic transmission that takes place over a network or internet. To do this it firstly encrypts the information i.e. codes it in such a way that the computer that is going to receive it can only decode or decrypt it. Kerberos also ensures that the users' password is never sent across wires instead password encrypted with keys are sent. This Kerberos is necessary to prevent people from tapping the lines and listening all the information specially passwords.