Question

What will be the ciphered text if the string “HELLO” is given as input to the code of hill cipher with keyword as “SANFOUNDRY”?

(a) EZJ

(b) JEZ

(c) ZEJ

(d) JZE

This question was posed to me during a job interview.

This intriguing question comes from Cryptography topic in division Cryptography of Data Structures & Algorithms II

Answer 1

Correct choice is (d) JZE

To explain: Hill cipher is a type of poly alphabetic substitution. It uses a n x n matrix in order to cipher the given plain text. Using this method we find the ciphered text to be JZE.