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# MCQ | Cryptography Ciphers (Level: Easy) | Set 2

Here, we have a set of **multiple-choice questions and answers (quiz) on ciphers in Cryptography** (basic concepts of Cryptography Techniques and different types of ciphers).

Submitted by Monika Sharma, on February 02, 2020

**1) You are supposed to use hill cipher for encryption technique. You are provided with the following matrix,**

A = [ 4 2 2 1 ]

**Is the given matrix 'A', a valid key to be used for encryption?**

- Yes
- No
- Can't be determined
- Data insufficient

**Answer:** b) No

**Explanation:**

For choosing any square matrix as a key, it should be taken care that the matrix is invertible, i.e. its inverse must exist. Here, in this case,

| A | = 0

Therefore, it means that 'A' is not an invertible matrix. Hence matrix 'A' cannot be chosen as a key matrix for encryption in the Hill cipher.

**2) The DES (Data Encryption Standard) cipher follows the fiestal structure. Which of the following properties are not shown by the fiestal structure?**

- The input text is divided into two parts: one being left half and another one being right half.
- Swapping of the left and right halves are performed after each round.
- The plain text is converted into a matrix form first
- None of the above

**Answer:** c) The plain text is converted into a matrix form first

**Explanation:**

The fiestal structure does not require the conversion of the plain text into matrix form at any of its steps.

**3) Among the following given options, chose the strongest encryption technique?**

- DES ( Data Encryption Standard)
- Double DES
- Triple DES
- AES (Advance Encryption Standard)

**Answer:** d) AES (Advance Encryption Standard)

**Explanation:**

It has been proved that the AES performs much better than the all the other DES, whether it be single DES or series of DES.

**4) What is the full-form of RSA in the RSA encryption technique?**

- Round Security Algorithm
- Rivest, Shamir, Adleman
- Robert, Shamir, Addie
- None of the above

**Answer:** b) Rivest, Shamir, Adleman

**Explanation:**

The RSA algorithm was named after the three scientists who developed this technique and the name RSA is itself the abbreviation of their names: Rivest, Shamir, and Adleman.

**5) Consider the following steps,**

- Substitution bytes
- Shift Rows
- Mix columns
- Add round key

**The above steps are performed in each round of which of the following ciphers?**

- Rail fence cipher
- Data Encryption Standard (DES)
- Advance Encryption Standard (AES)
- None of the above

**Answer:** c) Advance Encryption Standard (AES)

**Explanation:**

Each round of AES includes the mentioned steps.

**6) Codes and ciphers are different ways to _____ a message.**

- Encrypt
- Decrypt
- Both A and B
- All of the mentioned above

**Answer:** c) Both A and B

**Explanation:**

Codes and cyphers are two separate methods of encrypting and decrypting messages. Using a code, you may make any message more or less meaningful by substituting each word with another that has a different meaning.

**7) _____ ciphers encrypt uniformly sized blocks of data.**

- Set
- Block
- Rack
- All of the mentioned above

**Answer:** b) Block

**Explanation:**

Block cyphers are used to encrypt data in blocks of consistent size. A block cypher takes a block of plaintext bits and generates a block of ciphertext bits, which are typically the same size as the plaintext blocks they are given. In the given system, the size of the block is fixed at a certain size.

**8) Images can also be encrypted in sentences,**

- True
- False

**Answer:** A) True

**Explanation:**

Images can also be encoded in the form of phrases. Steganography is the term used to describe this. Steganography is a type of encryption procedure in which you write one thing but truly mean something completely different when you read it.

**9) Decryption is a process to unveil the ______.**

- Unsecured data
- Secured data
- Insecure
- None of the mentioned above

**Answer:** b) Secured data

**Explanation:**

Decryption is a process to unveil the secured data, and for it, the structure obtains and transforms the mixed-up data and modifies it into an accessible language and image for both the reader along the system.

**10) Symmetric encryption gathers plain-text data and then shuffles it to make it unreadable.**

- True
- False

**Answer:** a) True

**Explanation:**

Simple text data is collected and then shuffled in order to render it unreadable using symmetric encryption. And, just before it reaches the intended.

**More...**

- MCQ | Cryptography Basics
- MCQ | Cryptography Ciphers (Level: Easy) | Set 1
- MCQ | Cryptography Hash Functions (Level: Easy)
- MCQ | Cryptography Techniques of Block Cipher
- MCQ | Block Cipher as IDEA, DES, AES, RSA in Cryptography
- MCQ | Quantum Cryptography
- MCQ | Hash Function Technique
- MCQ | Modes of Operations in Block Cipher

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