Q3) a) Alice and Bob want to exchange an encryption key over an insecure communication link. For this purpose they agreed on a prime number 5, and its primitive roots 3. Alice chooses his private key 6 and Bob choose his private key as 7. Now compute the secret key using Diffie- Hellman Key Exchange? [6] b) Perform encryption and decryption using the RSA algorithm, for the following: p=7;q=11; e=17; M=8 and compare its performance with affine cipher? [6+3] c) Explain the Features of IPSEC at Network Layer. [5]