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 addressed to me during an interview for a job.

Enquiry is from Cryptography topic in chapter Cryptography of Data Structures & Algorithms II

Answer 1

The correct answer is (d) Additive cipher

The best 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.