Question

Which of the following is a mono alphabetic substitution cipher?

(a) vigenere cipher

(b) one time pad cipher

(c) play fair cipher

(d) atbash cipher

This question was posed to me in an international level competition.

My question is from Cryptography in division Cryptography of Data Structures & Algorithms II

Answer 1

The correct choice is (d) atbash cipher

Best explanation: Atbash cipher is the only mono alphabetic substitution cipher out of the given options. All the remaining options fall under the category of poly alphabetic cipher.