Question

Which of the following correctly defines poly alphabetic cipher?

(a) a substitution based cipher which uses multiple substitution at different positions

(b) a substitution based cipher which uses fixed substitution over entire message

(c) a transposition based cipher which uses multiple substitution at different positions

(d) a transposition based cipher which uses fixed substitution over entire message

I have been asked this question during a job interview.

Asked question is from Cryptography topic in portion Cryptography of Data Structures & Algorithms II

Answer 1

Right answer is (a) a substitution based cipher which uses multiple substitution at different positions

The best I can explain: Poly alphabetic cipher is a type of substitution cipher. It uses multiple substitution at different positions in order to cipher the plain text.