Cryptography > Home (15 min.)      

1) Know how to add and multiply numbers.

2) Have an open and inquisitive mind 

Have you ever wondered why you can place your credit card number on Amazon's web page to pay online and no eavesdropper (believe me there are many out there) could exploit it for his Christmas shopping? 
Do you want to know how the British cracked the fantastic ENIGMA machine of the Germans in World War II ? 
Have you ever wondered how you can keep your secrets on a computer for yourself although people may try very hard to find out? 

If so, or you just want to learn about cryptography - the science of encoding and decoding secret information - you are welcome to use this easy-to-use, interactive cryptography tutorial. You have the opportunity to learn the secrets of cryptography in 30 lessons without having any background knowledge. check prerequisites on left 

The tutorial ends with a cipher challenge > cipher challenge that you can break if you have mastered the ciphers introduced in this tutorial. Email the solution to the author in order to receive a precious prize.   

Additionally, please leave your tutorial feedback here. The author appreciates your input to continuously update and improve the tutorial.   

Course Overview

Objective: Learn the most prominent classical and modern ciphers to understand how modern encryption techniques can protect your privacy.

Who is this course for? Anybody interested learning cryptography.

Outline: View course outline at head menu of this page. Course order is from left to right, top to bottom.

Tutorial Version: 1.1 (15 March 2002) 

Lessons: 30 Lessons.

Time required: About 15 hours to work entire tutorial. Individual lessons vary between 15 - 45 min (listed on each page).  

Technical Requirements: Tutorial is best viewed with Internet Explorer (4.0+), 28.8kb connection or faster. 

Instruction style: A mixture of interactive web pages and instructional text.

How to benefit most: Attempt to break as many ciphers as possible on your own before reading how it is done. The interactive style allows you to test and refine your guesses. Don't move on until the cipher is mastered. The tutorial setup assumes a steady learning process.     

Fee: none

Incentive: Break the final Cipher Challenge to win a price. Additionally, certificate for successful course completion will be issued. 

Author: This course was created with the assistance of Dr. Michael Hortmann and Salvatore Angiletta, both from the University of Bremen, Germany.

Resources: Read the accompanying textbook  (written in WinWord format).  It explains the Ciphers and the underlying Mathematics in detail as well as shows and explains how to implement the ciphers in C++ programming language. Simply click on the provided links in the course pages, look for this symbol:    

Links to relevant web pages are provided on each course page as well. 

Feedback: Please leave your feedback on the tutorial usage here.  

Donations: Did you learn something new? We appreciate your support to keep the site up. Click on the Make a Donation button below.


Further Reading: 

- Singh, S. (1999). The Code Book

- Koblitz, N. (1987). A Course in Number Theory and Cryptography. New York: Springer-Verlag

- Schneier, B. (1994). Applied Cryptography. New York: John Wiley & Sons, Inc.

- Kahn, D. (1967). The Codebreakers: The story of secret writing. New York: Macmillan.

- Stephenson, N. (2000). Cryptonomicon, 900 pages, gives a great insight from historic to modern cryptography in a quasi-fiction manner.

- Kahn, D. (1991). Seizing the Enigma. Boston:Houghton Mifflin.

Get started


Related web sources:

Enigma and the History of Encryption

Yahoo's Encryption & Security


PBS Online

Introduction to Cryptography

Enigma History

Enigma Emulator