Question

What is poly graphic substitution cipher?

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

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

(c) a substitution based cipher in which substitution is performed over a block of letters

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

I had been asked this question in an interview for job.

The query is from Cryptography in section Cryptography of Data Structures & Algorithms II

Answer 1

The correct choice is (c) a substitution based cipher in which substitution is performed over a block of letters

The best I can explain: Poly graphic cipher is a type of substitution cipher in which substitution is performed over a block of letters. Hill cipher is an example of poly graphic cipher.