Cracking Codes with Python

13A MODULAR ARITHMETIC MODULE FOR THE AFFINE CIPHER

“People have been defending their own privacy for centuries with whispers, darkness, envelopes, closed doors, secret handshakes, and couriers. The technologies of the past did not allow for strong privacy, but electronic technologies do.”—Eric Hughes, “A Cypherpunk’s Manifesto” (1993)

In this chapter, you’ll learn about the multiplicative cipher and the affine cipher. The multiplicative cipher is similar to the Caesar cipher but encrypts using multiplication rather than addition. The affine cipher combines the multiplicative cipher and the Caesar cipher, resulting in a stronger and more reliable ...