1.4: Play fair Cipher Technique: Cryptography and System Security

Topics discussed: 1) Classical encryption techniques or Classical cryptosystems. 2) Basics of Playfair cipher and a general comparison of the cipher text with Caesar, Shift, and Monoalphabetic ciphers. 3) Important rules for encryption using Playfair ciphering technique. 4) Use of keyword and construction of 5x5 matrix using the keyword for the encryption process. 5) Creation of digrams and removal of repeating letters in digrams using filler letters. 6) Explanation of cryptanalysis on Monoalphabetic ciphers with example.