Ciphers and Such!

April 2021

Introduction

In this series, I want to try to code different encryption techniques. I’ll start with substitution ciphers, and possibly end with a one-time pad or an Enigma emulator. Who knows?

Vocabulary

• ASCII: A system to represent characters in a way a computer can understand. More specifically, a system for encoding characters (letters, numbers, symbols) in decimal, binary, and hexadecimal numbers.
  • This is the ASCII table I reference
• Substitution cipher: A method of encryption where each character is substituted for another character, using either a key or a mathematical function. Comes in 2 varieties:
  • Monoalphabetic Substitution cipher: Uses a single alphabet to encrypt a message. Examples include the Caesar cipher and ROT13.
  • Polyalphabetic Substitution cipher: Uses multiple alphabets to encrypt a message. Examples include the Vignère cipher and the Enigma machine.

Ciphers

• Caesar Cipher: One of the simplest and oldest ciphers. Simply a monoalphabetic substitution cipher.
• Affine Cipher: An even simpler monoalphabetic substitution cipher, where each letter only has very few encrypted equivalents.

More code can be found on this project’s GitHub repo.