Question

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

(a) autokey cipher

(b) rail fence cipher

(c) vigenere cipher

(d) additive cipher

I have been asked this question in an interview for job.

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

Answer 1

Correct option is (b) rail fence cipher

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