Question

Which of the following is not a type of poly alphabetic cipher?

(a) Rotor cipher

(b) Hill cipher

(c) One time pad cipher

(d) Multiplicative cipher

The question was asked during an interview.

This is a very interesting question from Cryptography in portion Cryptography of Data Structures & Algorithms II

Answer 1

The correct choice is (d) Multiplicative cipher

Easiest explanation - In poly alphabetic cipher each symbol of plain text is replaced by a different cipher text regardless of its occurrence. Out of the given options only multiplicative cipher is not a poly alphabetic cipher.