FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -The Caesar cipher is based on transposition and involves shifting each letter of the plaintext message by a certain number of letters, historically three, as shown in Figure 5.1. The ciphertext can be decrypted by applying the same number of shifts in the opposite direction.

Detailed explanation-2: -In order to decode your message, you need to share the “key” (the number 3) with your friend. After that you can send messages that are written in cipher so other people can’t read them! Explain the concept of a Caesar cipher to a friend or have them read the background section of this activity.

Detailed explanation-3: -The Caesar cipher is named after Julius Caesar, who, according to Suetonius, used it with a shift of three (A becoming D when encrypting, and D becoming A when decrypting) to protect messages of military significance.

Detailed explanation-4: -To decrypt a message, enter the message in the Ciphertext textbox, specify the shift, and click Decrypt. Note that, in this implementation, strings are converted to upper case before encryption/decryption, and spaces and punctuation marks are not encrypted/decrypted.

Detailed explanation-5: -Numbers expands the alphabet and are included to the rotations. Other symbols except letters and numbers are not transformed. The classic Caesar cipher applies transformation only to letters. Transformation, known as ROTN, where ROT is from “ROTATE” and N is the value of cyclical shift, defines letter substitution.