# Columnar Transposition Multiple Choice Questions and Answers (MCQs)

This set of Data Structures & Algorithms Multiple Choice Questions & Answers (MCQs) focuses on “Columnar Transposition”.

1. Which of the following is not a type of traditional cipher?
a) Substitution cipher
b) Transposition cipher
c) Mono alphabetic cipher
d) PKCS cipher

Explanation: There are two types of the traditional cipher. One is transposition cipher and the other is substitution cipher. Whereas PKCS is a modern asymmetric cipher.

2. Which of the following cipher uses two keys to encrypt data?
a) substitution cipher
b) transposition cipher
c) symmetric cipher
d) asymmetric cipher

Explanation: Asymmetric cipher makes use of 2 keys for the purpose of encryption. One is known as public key whereas other is called private key.

3. Asymmetric encryption is also known as?
a) Private key cryptography
b) Public key cryptography
c) Public private key cryptography

Explanation: Asymmetric encryption is also known as public key cryptography. Asymmetric cipher makes use of 2 keys for the purpose of encryption.

4. Which of the following is an example of asymmetric encryption technique?
c) DSA
d) blowfish

Explanation: Asymmetric cipher makes use of 2 keys for the purpose of encryption. DSA is an example of asymmetric encryption technique.

5. Columnar cipher falls under the category of?
a) mono-alphabetic cipher
b) poly-alphabetic cipher
c) transposition cipher

Explanation: Columnar cipher is a transposition cipher. It falls under the category of transposition cipher as it encrypts the plain text by rearranging its letters.

6. Which of the following ciphered text would have NOT used transposition cipher for encryption of the plain text “CIPHER”?
a) EPIHRC
b) EHIPCR
c) DTIPRC
d) HRIPEC

Explanation: We know that transposition cipher encrypts the plain text by shuffling the letters of the plain text. So out of the given options, only “DTIPRC” does not have the same set of letters as “CIPHER”.

7. Which of the following cipher is formed by applying columnar transposition cipher twice?
a) Rail Fence cipher
b) Route cipher
c) Double transposition cipher

Explanation: Double transposition cipher is formed by applying columnar transposition cipher twice. For the purpose of encryption, we may use the same key twice or we can use two different keys.

8. In which of the following cipher the plain text and the ciphered text does not have the same set of letters?
a) route cipher
b) columnar transposition cipher
c) myszkowski cipher

Explanation: In transposition cipher, the letters remain the same in ciphered and plain text. Their position is only changed whereas in substitution cipher the letters become different in encrypted text. As additive cipher is the only non transposition cipher out of the given options so it will be the correct option.

9. Columnar transposition cipher is harder to crack as compared to double transposition cipher?
a) true
b) false

Explanation: Double transposition cipher is formed by applying columnar transposition cipher twice. So it is harder to crack than a simple columnar transposition cipher.

10. How many columns do we need to have in the table, that is used for encryption in columnar transposition cipher when a given keyword is “SECRET” and plain text is “SANFOUNDRY”?
a) 4
b) 5
c) 6
d) 7

Explanation: The number of columns in the table used for the purpose encryption in columnar transposition cipher will always be equal to the number of letters in the keyword. So in this case it will be equal to 6.

11. What will be the encrypted text corresponding to plain text “CLASSIFIED” using columnar transposition cipher with a keyword as “GAMES”?
a) LFDSIASECI
b) SECIAISDFL
c) CILFAISESD
d) LFSECIAISD

Explanation: For encrypting using columnar cipher we have to arrange the letters of the plain text in a table which has the same number of columns as the letters of the keyword. Then the letters of the keyword are arranged in alphabetical order and we read along each column.
3 1 4 2 5
G A M E S
C L A S S
I F I E D
So the ciphered text will be “IFSECIAISD”.

12. How many rows will the letters of the plain text occupy in the table, that is used for encryption in columnar transposition cipher when a given keyword is “SECRET” and plain text is “SANFOUNDRY”?
a) 1
b) 2
c) 3
d) 4

Explanation: The number of columns in the table used for the purpose encryption in columnar transposition cipher will always be equal to the number of letters in the keyword.So when we will write the letters of the plain text row wise then there will be 2 rows of plain text in this case. The table is shown below :-
S E C R E T
1 S A N F O U
2 N D R Y

13. Which of the following statement is not true regarding columnar transposition cipher?
a) it is a weak cipher
b) probability of error is high while deciphering
c) it cannot be combined with other ciphers
d) it is a traditional symmetric cipher

Explanation: Although columnar transposition cipher is a weak cipher in itself. But it can be combined with other substitution ciphers so as to improve its security. The probability of error remains high while decoding columnar cipher as it is a lengthy process.

Sanfoundry Global Education & Learning Series – Data Structures & Algorithms.

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