Question

What is the formula used for encryption of data using affine cipher(a,b are constants and x is the numerical equivalent of a letter to be encrypted)?

(a) ax+b

(b) (ax+b)%26

(c) ax^2+bx

(d) (ax^2+bx)%26

This question was addressed to me in class test.

I need to ask this question from Cryptography in division Cryptography of Data Structures & Algorithms II

Answer 1

The correct choice is (b) (ax+b)%26

To explain: Affine cipher uses linear algebra for the purpose of encryption. It uses the formula (ax+b)%26 for this purpose.