1. Discuss the notion of keys in cryptography.

Is a block better than a stream?

Please note, maximum number of words – 150

2. 

Differentiate block ciphers from stream ciphers and contrast symmetric from asymmetric cryptography. Illustrate with examples. (Maximum: Half a Page)

(a) Compare monoalphabetic and polyalphabetic ciphers.

(b) Using the Caesar Cipher method, crack this coded message – decrypt the ciphertext – WXWRULDO.

Illustrate your work.

(Maximum: Half a Page)