# Gronsfeld Cipher Multiple Choice Questions and Answers (MCQs)

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

1. Gronsfeld cipher is an example of _____________
a) mono-alphabetic cipher
b) poly-alphabetic cipher
c) transposition cipher

Explanation: Gronsfeld cipher is a substitution cipher. It falls under the category of poly alphabetic cipher as it uses multiple substitutions at different positions in order to cipher the plain text.

2. Which of the following is true about encryption in gronsfeld cipher?
a) It replaces letters with numbers
b) It shifts the letters of plain text on the basis of key value
c) It makes substitutions by using tabula recta
d) It makes substitutions on the basis of a mathematical formula

Explanation: Encryption of plain text in gronsfeld cipher is done by shifting the letters of plain text on the basis of key value. So it is similar to caesar cipher.

3. Gronsfeld cipher is similar to?
b) multiplicative cipher
c) caesar cipher
d) affine cipher

Explanation: In gronsfeld cipher we shift the letters of the plain text on the basis of the key value. So it becomes a modified version of the caesar cipher.

4. Which of the following cipher uses a numeric key?
a) gronsfeld cipher
b) vigenere cipher
c) trithemius cipher
d) running key cipher

Explanation: Gronsfeld cipher is a variation of vigenere cipher. The difference is that vigenere cipher uses an alphabetical key whereas gronsfeld cipher uses numeric key.

5. Which of the following cipher does not require the use of tabula recta?
a) running key cipher
b) vigenere cipher
c) gronsfeld cipher
d) trithemius cipher

Explanation: Ciphers like running key cipher, vigenere cipher, trithemius cipher etc. makes use of tabula recta. Whereas gronsfeld cipher does not require tabula recta for encryption of plain text.

6. Gronsfeld cipher is a variation of ____________
a) autokey cipher
b) vigenere cipher
c) hill cipher
d) route cipher

Explanation: Gronsfeld cipher is a variation of vigenere cipher. The difference is that vigenere cipher uses an alphabetical key whereas the key of gronsfeld cipher consists of numbers.

7. Gronsfeld cipher is harder to crack than caesar cipher.
a) True
b) False

Explanation: In gronsfeld cipher we shift the letters of the plain text on the basis of the key value. So it becomes a more complex version of the caesar cipher and thus harder to crack.

8. What will be the plain text corresponding to cipher text “EETPEG” if gronsfeld cipher is used with key “4321”?
a) ABACUS
c) ABRUPT
d) ABUSED

Explanation: Encryption in gronsfeld cipher takes place by shifting the letters of the plain text by a number given by the numeric key. So by applying the reverse of this method, we get the deciphered text to be “ABROAD”.

9. Gronsfeld cipher is a substitution cipher.
a) True
b) False

Explanation: Gronsfeld cipher is a type of substitution cipher. It is a variation of vigenere cipher.

10. Which of the following is not a transposition cipher?
a) rail fence cipher
b) gronsfeld cipher
c) hill cipher
d) route cipher

Explanation: Rail fence, hill and route cipher are examples of transposition cipher. Gronsfeld cipher is a substitution cipher and so is the correct option.

11. What will be the ciphered text corresponding to “SANFOUNDRY” if gronsfeld cipher is used for encryption with key as “1234”?
a) TCQJPWQHSA
b) TCQJTAULAI
c) TCQJOUNDRY
d) UETNQYTLTC

Explanation: Encryption in gronsfeld cipher takes place by shifting the letters of the plain text by a number given by the numeric key. So by applying this method, we get the ciphered text to be “TCQJPWQHSA”.

12. What will be the ciphered text corresponding to “ALGORITHM” if gronsfeld cipher is used for encryption with key “4321”?
a) BNJSSKWLN
b) EOIPVLVIQ
c) BNJSRITHM
d) EOIPRITHM

Explanation: Encryption in gronsfeld cipher takes place by shifting the letters of the plain text by a number given by the numeric key. So by applying this method, we get the ciphered text to be “EOIPVLVIQ”.

13. What will be the plain text corresponding to cipher text “SCEFJV” if gronsfeld cipher is used with key “1234”?
a) RABBIT
b) RUSSIA
c) RANGER
d) FRIEND

Explanation: Encryption in gronsfeld cipher takes place by shifting the letters of the plain text by a number given by the numeric key. So by applying the reverse of this method, we get the deciphered text to be “RABBIT”. 