Question

What is the period in bifid cipher?

(a) length of blocks in which the plain text is divided before encryption

(b) number of letters after which the key is repeated

(c) number of blocks into which the plain text is divided before encryption

(d) number of keys used for encryption

The question was asked in an online interview.

This is a very interesting question from Cryptography in chapter Cryptography of Data Structures & Algorithms II

Answer 1

The correct answer is (a) length of blocks in which the plain text is divided before encryption

The best explanation: Polybius square is similar to substitution cipher. It is also known by the name of Polybius checkboard.