## Frequency Analysis

In cryptography, frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking substitution ciphers (e.g. mono-alphabetic substitution cipher, Caesar shift cipher, Vatsyayana cipher). Frequency

## Mono-Alphabetic Substitution Cipher

A mono-alphabetic cipher (aka simple substitution cipher) is a substitution cipher where each letter of the plain text is replaced with another letter of the alphabet. It uses a fixed key which consist of the 26 letters of a “shuffled

## Enigma Encoder

The Enigma machines are a series of electro-mechanical rotor cipher machines. The first machines were invented at the end of World War I by German engineer Arthur Scherbius and were mainly used to protect commercial, diplomatic and military communication. Enigma

## Turing-Welchman Bombe Simulator

In our Enigma – mission X challenge, we looked at how the Enigma machine was used by the Germans during WWII to encrypt radio communications and how code breakers were assigned the job to crack the code of the Enigma

## Enigma Daily Settings Generator

Before attempting this challenge, you should familiarise yourself with the Enigma machine by completing the Enigma Mission X challenge. Code Books were used by the Germans to list all the settings needed to set up the Enigma machines before starting

## Enigma – Mission X Challenge

Dear code breaker, I am contacting you from Bletchley Park as we are intercepting an increased volume of encrypted radio signals. We are working day and night to break the enigma codes that the German Navy are updating every day.

## Enigma Machine Emulator

The Enigma machines are a series of electro-mechanical rotor cipher machines. The first machines were invented at the end of World War I by German engineer Arthur Scherbius and were mainly used to protect commercial, diplomatic and military communication. Enigma

## Symmetric vs. Asymmetric Encryption

Cryptography is the art of encoding and decoding secret messages. Cryptographic techniques have been used for thousands of years, well before the introduction of computers, and the techniques have evolved since. (e.g. See how the Caesar Cipher was used by

## The Pigpen Cipher

The Pigpen cipher (a.k.a. tic-tac-toe cipher) is a geometric substitution cipher, which exchanges letters for symbols which are fragments of a grid. Secret Message Using the key provided on the right, can you decode the following secret message?   Pigpen

## The Rail Fence Cipher

The rail fence cipher (sometimes called zigzag cipher) is a transposition cipher that jumbles up the order of the letters of a message using a basic algorithm. The rail fence cipher works by writing your message on alternate lines across