question archive Answer the following questions related to key management: a
Answer the following questions related to key management: a
Subject:Computer SciencePrice: Bought3
Answer the following questions related to key management: a. In the given figure, what happens if the ticket for Bob is not encrypted in step 2 with KB, but is encrypted instead by KAB in step 3? (Marks: 2) KA Encrypted with Alice-KDC secret key Session key between Alice and Bob KB Encrypted with Bob-KDC secret key KDC: Key-distribution center KDC Alice Bob Alice, Bob KB 2 Alice, Bob, KB Alice, Bob, f b. Why do you think we need only one timestamp in Kerberos instead of four nonces as in Needham-Schroeder or three nonces as in Otway-Rees? (Marks: 2) c. Assume that the user's password is not stored on the client machine, and the client's key KC is computed from the user's password by a known function. Why is Kerberos more convenient, for the human user, than a system in which the TGS is eliminated, and the client makes a Kerberos-style request to the KDC for each server connection? (Marks: 2) d. In Kerberos v4, it is possible for an attacker to request a ticket for C, or simply overhear a request and response for C. How this allows an attacker to do an offline dictionary attack. (Marks: 2) e. In Kerberos v5, a nonce, or random number, is added to the client's request to the KDC, and included (as part of the encrypted response) in the reply 2/3 Page HAL ISLAMIC INTERNATIONAL ISLAMIC UNIVERSITY ISLAMABAD ALISHAMIND Faculty of Basic and Applied Science ISLAMABAD Department of Computer Science and Software Engineering from the KDC. Nonces are similarly used in the request and response from the TGS. What purpose does this serve?
