Question

Auto key cipher is more secure than polybius square cipher?

(a) true

(b) false

This question was addressed to me at a job interview.

This intriguing question originated from Cryptography in section Cryptography of Data Structures & Algorithms II

Answer 1

The correct choice is (a) true

Easiest explanation - Polybius square is closely related to mono alphabetic substitution cipher and thus is more vulnerable to frequency analysis. Whereas polybius square being a poly alphabetic cipher is less vulnerable to frequency analysis and so is more secure.