Question

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

(a) Autokey cipher

(b) Hill cipher

(c) One time pad cipher

(d) Additive cipher

This question was posed to me during an interview.

Query is from Cryptography in chapter Cryptography of Data Structures & Algorithms II

Answer 1

Correct choice is (d) Additive cipher

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 additive cipher is not a poly alphabetic cipher.