Somebody created a modified Kerberos protocol. The figure below shows the exchange between Client and Service Server of the modified protocol (other parts as discussed in lecture are not shown here).

a) Explain one attack that may be applied specifically against this modified Kerberos protocol exchange shown below. (4 marks)

b) Explain how to fix the security issue in the modified Kerberos protocol. Your solution must be justified and refer to details of the protocol. (6 marks)

c) Discuss a practical requirement for this fix to work. (3 marks)