Question

Autokey cipher is an example of ___________

(a) mono-alphabetic cipher

(b) poly-alphabetic cipher

(c) transposition cipher

(d) additive cipher

This question was addressed to me during an interview.

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

Answer 1

The correct option is (b) poly-alphabetic cipher

Easiest explanation - Autokey cipher is a substitution cipher. It falls under the category of poly alphabetic cipher as it uses multiple substitutions at different positions in order to cipher the plain text.