Question

Encryption in hill cipher is done using ______________

(a) matrix multiplication

(b) a 5×5 table

(c) vigenere table

(d) matrix inversion

This question was posed to me in an interview for internship.

Question is taken from Cryptography topic in section Cryptography of Data Structures & Algorithms II

Answer 1

The correct option is (a) matrix multiplication

Easiest explanation - Encryption of plain text in playfair cipher is done using matrix multiplication. Then modulo 26 of the resulting matrix is taken so as to get the ciphered text.