Data Structures & Algorithms Multiple Choice Questions on “Gronsfeld Cipher”.
1. Gronsfeld cipher is an example of _____________
a) mono-alphabetic cipher
b) poly-alphabetic cipher
c) transposition cipher
d) additive cipher
Answer: b
Clarification: 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
Answer: b
Clarification: 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?
a) additive cipher
b) multiplicative cipher
c) caesar cipher
d) affine cipher
Answer: c
Clarification: 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
Answer: a
Clarification: 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
Answer: c
Clarification: 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 ____________ Answer: b 7. Gronsfeld cipher is harder to crack than caesar cipher. 8. What will be the plain text corresponding to cipher text “EETPEG” if gronsfeld cipher is used with key “4321”? Answer: b 9. Gronsfeld cipher is a substitution cipher. Answer: a 10. Which of the following is not a transposition cipher?
a) autokey cipher
b) vigenere cipher
c) hill cipher
d) route cipher
Clarification: 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.
a) True
b) False
Answer: a
Clarification: 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.
a) ABACUS
b) ABROAD
c) ABRUPT
d) ABUSED
Clarification: 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”.
a) True
b) False
Clarification: Gronsfeld cipher is a type of substitution cipher. It is a variation of vigenere cipher.
a) rail fence cipher
b) gronsfeld cipher
c) hill cipher
d) route cipher