1. The sender do the following operations on message m before sending it:
   1. Protocol A:

c=ek1[m h(k2x)]

where e is a private-key encryption algorithm, m is the message sent, h() is a hashing function ( such as SHA-1), || indicates a concatenation, and k1, k2 are secret keys which are stored only at sender and receiver.

2. Protocol B:

c=ek1[m sigkpr(hm)]

Explain in details which the processes that the receiver will do step-by-step upon receipt of c [8 Marks].

b) The sender do the following operations on message m before sending it: 1. Protocol A: C = eki[m || h(k2 || x)] where me is a private-key encryption algorithm, m is the message sent, h() is a hashing function ( such as SHA-1), Il" indicates a concatenation, and k1, k2 are secret keys which are stored only at sender and receiver. 2. Protocol B: c = eki[m || sigkpr (h(m))] Explain in details which the processes that the receiver will do step-by-step upon receipt of c [8 Marks)