Question

To encrypt a message _______ is used on the character’s positions.

(a) boolean algebra

(b) bijective function

(c) inverse function

(d) surjective function

This question was posed to me in a job interview.

Origin of the question is Cryptography in portion Number Theory and Cryptography of Discrete Mathematics

Answer 1

Right answer is (b) bijective function

Best explanation: We have a mathematical notion that a bijective function can be used on the characters’ positions to encrypt a message and an inverse function is used to decrypt the message.