Caesar Cipher Concepts and Techniques

The video tutorial introduces the Caesar Cipher, a classical encryption technique. It explains the substitution method used in the cipher, where each letter in the plaintext is replaced by a letter three positions down the alphabet. The tutorial covers the algorithm for both encryption and decryption, using mod 26 to handle the alphabet's circular nature. An example is provided to demonstrate the encryption process, and a homework assignment is given to practice decryption. The session concludes with a brief mention of the next topic: crypto analysis of Caesar Cipher.

What is the primary outcome of the session on Caesar Cipher?

• Understanding the history of cryptography

• Learning about transposition techniques

• Understanding Caesar Cipher with examples

• Exploring modern encryption methods

Which of the following is NOT a classical encryption technique?

• Caesar Cipher

• Quantum Encryption

• Transposition

• Substitution

In Caesar Cipher, how are the letters of the plaintext replaced?

• By numbers

• By letters two places up the alphabet

• By letters three places down the alphabet

• By symbols

What is the key value used in Caesar Cipher?

• 2

• 3

• 10

• 5

What is the purpose of the mod 26 operation in Caesar Cipher?

• To encrypt numbers

• To decrypt the text

• To increase security

• To ensure letters wrap around the alphabet

What is the encrypted form of the letter 'N' using Caesar Cipher?

• R

• P

• O

• Q

How is the letter 'E' encrypted in Caesar Cipher?

• I

• F

• G

• H

What is the encrypted form of the word 'neso' using Caesar Cipher?

• qhvr

• qhur

• qhts

• qhtv

What is the first step in decrypting a message using Caesar Cipher?

• Divide by the key value

• Multiply by the key value

• Subtract the key value

• Add the key value

What is the key value used in the homework question for decryption?

• 4

• 3

• 2

• 1