# Encryption Class Week 1

I am studying for the E-Councils Encryption Specialist Certification. I will be publishing what I have learned on the way to test for this certification.

What is Cryptography?

The word is derived from the word kryptos, which means hidden, and the verb grafo which means write. Here is the official definition from Webster’s dictionary:

**Mono-Alphabet Substitution**

The Mono-Alphabet Substitution is the oldest and simplest cryptographic algorithm. The Mono-Alphabet Substitution algorithms work by substituting one character of the ciphertext, which is the result of the encryption of the plain text, with the plain text. The Caesar Cipher, Atbash Cipher, and the Affine Cipher, and the Rot 13 Cipher are all examples of the Mono-Alphabet Substitution algorithm.

**Caesar Cipher**

The Caesar Cipher was used by Julis Caesar and the Romans. This cipher works by shifting specified spaces in the alphabet to the left or to the right. In a Caesar Cipher, the key is the shift. So if you had the phrase, **“Deadpool is the best superhero” with a key of 3+, the ciphertext would be: Ghdgsrro lv wkh ehvw vxshukhur. **This encryption is very simple to crack the key, it is not recommended to be used to encrypt sensitive information, but it is a good place to start learning ciphers.