Stream Ciphers, Random Numbers, and the One-Time Pad

Symmetric cryptography is split into two types, stream ciphers, and block ciphers. Stream ciphers encrypt one bit at a time and block ciphers encrypt multiple bits at a time. This post is dedicated to stream ciphers, if you want to learn about block ciphers make sure to read my DES and AES posts. Stream Ciphers […]

The Shift Cipher

The shift cipher, or the better-known name the Caesar cipher named after Julius Caesar is one of the simplest encryption techniques. In fact for those who have read my Substitution cipher post, the shift cipher is a type of substitution cipher where each letter in the alphabet is mapped to another fixed letter in the […]

Introduction to Modular Arithmetic

Modular Arithmetic     An important question and one that I kept asking if I should dedicate a post to modular arithmetic is “Why is this important?”, and I came to conclude that while at first modular arithmetic can be very easy/ natural at first, it also gets very abstract the further into cryptography we […]

The Substitution Cipher

The Substitution Cipher     We will discuss one of the simplest ciphers, the substitution cipher. This cipher has a lot of historical relevance being used many times, and is also a good starting point for cryptography and cryptanalysis. It is important to have read the What is Cryptology post because I will use concepts […]

What is Cryptology

What is Cryptology? The Oxford Dictionary defines Cryptology as: “the study of codes, or the art of writing and solving them”. When some people think of Cryptology people may think of secure website access, bank cards, or more modern “Cryptocurrency”. All of these would be correct, but cryptology is actually a much older business than […]