Question

What is the rule for encryption in playfair cipher if the letters in a pair does not appear in same row or column?

(a) they are replaced by the letter appearing immediately below them respectively

(b) they are replaced by the letter appearing immediately right to them respectively

(c) they are replaced by the letter of the same row at the corner of the rectangle defined by the original pair respectively

(d) that pair is neglected

I got this question in final exam.

The question is from Cryptography in portion Cryptography of Data Structures & Algorithms II

Answer 1

The correct answer is (c) they are replaced by the letter of the same row at the corner of the rectangle defined by the original pair respectively

The best I can explain: If the letters in a pair does not appear in same row or column then they are replaced by the letters of the same row at the corner of the rectangle defined by the original pair respectively. The order of letters should be maintained.