# FUNDAMENTALS OF COMPUTER

## COMPUTER THREATS SECURITY

### TYPES OF NETWORK SECURITY

 Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Encrypt “attack” with “fall” using Playfair Cipher
 A BRRBER B BERBFP C BRFFFP D BRRBFP
Explanation:

Detailed explanation-1: -Encryption rules: Playfair Cipher Split the plaintext first into digraphs (pairs of two letters). If the plaintext has an odd number of letters, append the letter Z at the end. Even the text in the basic form of The MANGO plaintext, for instance, consists of five letters.

Detailed explanation-2: -In this mission you will try to break the Playfair Cipher using known plaintext attack.

Detailed explanation-3: -The Playfair cipher uses a 5×5 grid of letters, and encrypts a message by breaking the text into pairs of letters and swapping them according to their positions in a rectangle within that grid: “HI” becomes “BM".

Detailed explanation-4: -In playfair cipher unlike traditional cipher we encrypt a pair of alphabets(digraphs) instead of a single alphabet. It was used for tactical purposes by British forces in the Second Boer War and in World War I and for the same purpose by the Australians during World War II.

There is 1 question to complete.