QUESTION 3 a) What three categories of information may be used as the basis of identification? b) How do challenge-response protocols improve upon the weak authentication provided by time-invariant protocols? c) Below is a challenge-response response protocol that aims to provide mutual authentication between two parties that share a secret key: (1) AB:Na (3) AB:Nb Analyse the sequence of challenges and responses in this protocol. Is the protocol secure (i.e. can you construct an attack against it that subverts its security objective)