<Li> Message C: Composed of the TGT from message B and the ID of the requested service . </Li> <Li> Message D: Authenticator (which is composed of the client ID and the timestamp), encrypted using the Client / TGS Session Key . </Li> <Li> Upon receiving messages C and D, the TGS retrieves message B out of message C. It decrypts message B using the TGS secret key . This gives it the "client / TGS session key". Using this key, the TGS decrypts message D (Authenticator) and compare client ID from message C and D, if they match server sends the following two messages to the client: <Ul> <Li> Message E: Client - to - server ticket (which includes the client ID, client network address, validity period and Client / Server Session Key) encrypted using the service's secret key . </Li> <Li> Message F: Client / Server Session Key encrypted with the Client / TGS Session Key . </Li> </Ul> </Li> <Ul> <Li> Message E: Client - to - server ticket (which includes the client ID, client network address, validity period and Client / Server Session Key) encrypted using the service's secret key . </Li> <Li> Message F: Client / Server Session Key encrypted with the Client / TGS Session Key . </Li> </Ul>

Explain in detail what kerberos tries to solve