Question

How many columns do we need to have in the table, that is used for encryption in columnar transposition cipher when a given keyword is “SECRET” and plain text is “SANFOUNDRY”?

(a) 4

(b) 5

(c) 6

(d) 7

This question was addressed to me in an internship interview.

Question is from Cryptography in portion Cryptography of Data Structures & Algorithms II

Answer 1

The correct answer is (c) 6

The explanation is: The number of columns in the table used for the purpose encryption in columnar transposition cipher will always be equal to the number of letters in the keyword. So in this case it will be equal to 6.