# MCQ | Cryptography Techniques of Block Cipher

Here, we have a **set of multiple-choice questions and answers (quiz) on Cryptography Techniques of Block Cipher**.

Submitted by Monika Sharma, on March 22, 2020

**1) What is the block size of plain text in SHA- 512 algorithm?**

- 512 bits
- 1024 bits
- 2048 bits
- None of the above

**Answer:** b. 1024 bits

**Explanation:**

The SHA- 512 algorithm uses blocks of plain text one at a time to encrypt them into ciphertext. The size of each block in the SHA- 512 algorithm is 1024 bits.

**2) All the below-stated processes are performed in the AES (Advanced Encryption Standard) Algorithm. Which of the following process(s) are not performed in the final round of the AES?**

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

**Options**

- i.
- iii.
- All of the mentioned
- None of the mentioned

**Answer:** b. iii.

**Explanation:**

In the AES algorithm, the MIX COLUMN operation is performed in all the rounds except the final round of the algorithm.

**3) What does IDEA stand for in the world of cryptography?orThe IDEA word in the IDEA algorithm is the abbreviation for which of the following? **

- Independent Decryption Environment Analysis
- International Defense Encryption Area
- International Data Encryption Algorithm
- None of the above

**Answer:** c. International Data Encryption Algorithm

**Explanation:**

The IDEA Algorithm stands for "International Data Encryption Algorithm".

**4) How many sub-keys in the total are used by the IDEA for encrypting the plain text into ciphertext?**

- 64 sub- keys
- 48 sub- keys
- 52 sub- keys
- Only one key and no subkeys

**Answer:** c. 52 sub- keys

**Explanation:**

There are a total of 8 rounds in the IDEA technique for encryption and each of them uses 6 keys. Apart from that, 4 extra keys are used in the final round that is the output transformation round. This gives us a total of 52 subkeys.**(8 x 6) + 4 = 52**

**5) "The number of rounds in the AES algorithm depends upon the key size being used."Which among the following shows a correct relation between the size of the key used and the number of rounds performed in the AES algorithm?**

- 128 key size: 10 rounds
- 192 key size: 12 rounds
- 256 key size: 14 rounds
- All of the above

**Answer:** d. All of the above

**Explanation:**

All the mentioned options display the correct relation between the number of rounds and the key size used in the AES algorithm.

**6) Which of the following properties are the characteristic properties of a block cipher technique which differs from stream cipher?**

- Avalanche effect
- Completeness
- Both a. and b.
- None of the above

**Answer:** c. Both a. and b.

**Explanation:**

Avalanche effect and Completeness are the two characteristic properties of Block ciphers which differ them from stream ciphers.

TOP Interview Coding Problems/Challenges

- Run-length encoding (find/print frequency of letters in a string)
- Sort an array of 0's, 1's and 2's in linear time complexity
- Checking Anagrams (check whether two string is anagrams or not)
- Relative sorting algorithm
- Finding subarray with given sum
- Find the level in a binary tree with given sum K
- Check whether a Binary Tree is BST (Binary Search Tree) or not
- 1[0]1 Pattern Count
- Capitalize first and last letter of each word in a line
- Print vertical sum of a binary tree
- Print Boundary Sum of a Binary Tree
- Reverse a single linked list
- Greedy Strategy to solve major algorithm problems
- Job sequencing problem
- Root to leaf Path Sum
- Exit Point in a Matrix
- Find length of loop in a linked list
- Toppers of Class
- Print All Nodes that don't have Sibling
- Transform to Sum Tree
- Shortest Source to Destination Path

Comments and Discussions

**Ad:**
Are you a blogger? Join our Blogging forum.