Lab 3 : Classic Cryptography

1. What is the difference between monoalphabetic and polyalphabetic encipherment? Monoalphabetic cipher: Here a single cipher alphabet is used. Polyalphabetic cipher: Here a set of related mono alphabetic substitution rules is used.
2. Decrypt the following Caesar cipher text





Plaintext (by using shift-13 Ceaser Cipher): WEST ART THE ATTACK AT EIGHT PM TO NIGHT BEG I BY ATTACKING THE MAIN POST OUR OBJECTIVE IS TOTAL DESTRUCTION OF THE ENEMY BASED SPARE NO ONE AND ANYTHING DESTROY EVERYTHING ON YOUR PATH.

3. Decrypt the following Vigeneré cipher text

By using Google search kasiski method to help you in solving this problem

Plaintext: JULIUS CAESAR USED A CRYPTO SYSTEM IN HIS WAR WHICH IS NO REFERRED TO AS CAESAR CIPHER. IT IS AS HIT CIPHER WITH THE KEY