Decryption and Cipher Techniques

The video tutorial introduces cryptography, focusing on encryption and decryption. It explains the Caesar cipher, a simple encryption method, and provides practical examples of encrypting and decrypting messages. The tutorial also covers general shift ciphers and introduces the affine cipher, highlighting their mathematical foundations and applications.

What is the primary goal of cryptography?

• To make data easily accessible

• To transform information so it cannot be easily recovered without special knowledge

• To share information with everyone

• To delete information permanently

What is the purpose of using a key in cryptography?

• To delete data securely

• To unlock encrypted data

• To create a backup of data

• To make data readable by everyone

Which of the following is NOT a part of the encryption process?

• Transforming plaintext into ciphertext

• Using a key to encrypt data

• Making data recognizable to unauthorized users

• Securing data during transmission

Which of the following is an example of plaintext?

• A key used for decryption

• Original message before encryption

• Encrypted message

• Random sequence of numbers

What happens to data during the decryption process?

• It is returned to its original form

• It is transformed into ciphertext

• It becomes more secure

• It is deleted

Who is credited with creating the Caesar cipher?

• Alan Turing

• Leonardo da Vinci

• Albert Einstein

• Julius Caesar

In the Caesar cipher, what does the term 'shift' refer to?

• Swapping numbers with letters

• Moving letters forward or backward in the alphabet

• Reversing the entire message

• Changing the order of words

What is the result of encrypting the letter 'M' using a Caesar cipher with a shift of 3?

• O

• Q

• N

• P

In the Caesar cipher, what does 'mod 26' refer to?

• The number of letters in the alphabet

• The number of words in a sentence

• The number of keys available

• The number of characters in a message

What is the encrypted form of the letter 'E' using a Caesar cipher with a shift of 3?

• I

• G

• H

• F