(a) Describe DES encryption with a block diagram and brief steps.
(b) How does triple DES improve security. What is the effective key length of triple DES? How can 3DES be compatible with DES?
(c) Describe a one way hash function and give an example. Give essential properties of the hash functions.
(d) Define message authentication. Explain MAC.
(e) Give three known attacks on AES encryption.