Question

In which of the following cipher the plain text and the ciphered text have same set of letters?

(a) one time pad cipher

(b) columnar transposition cipher

(c) playfair cipher

(d) additive cipher

I had been asked this question in my homework.

Question is taken from Cryptography topic in section Cryptography of Data Structures & Algorithms II

Answer 1

Right option is (b) columnar transposition cipher

For explanation: In transposition cipher, the letters remain same in ciphered and plain text. Their position is only changed whereas in substitution cipher the letters become different in encrypted text. So columnar transposition cipher will be the correct option.