Question

What will be the ciphered text if the string “SANFOUNDRY” is given as input to the code of playfair cipher with keyword as “SECRET” (assuming j is combined with i)?

(a) ZHQAPNPAFR

(b) AHQAPNPAFR

(c) HAQAPNPAFR

(d) QHAAPNPAFR

The question was asked in unit test.

My question comes from Cryptography topic in division Cryptography of Data Structures & Algorithms II

Answer 1

Correct option is (b) AHQAPNPAFR

Easiest explanation - For encrypting the plain text using playfair cipher we use a 5×5 table that is constructed by using keyword. Then we apply rules for encryption in order to get the ciphered text. Table is given as under-