Thomas Jefferson Monticello: Wheel Cipher
This page is from the website of Thomas Jefferson's home, Monticello, and discusses the history and mechanics of Jefferson's Wheel Cipher.
Computer Code Cracking and Cryptology
This article provides a comprehensive history of the British cryptoanalysts who broke the Enigma Machine code during World War II.
+Plus Magazine: Exploring the Enigma
This site provides extensive information on the Enigma Machine, including history, classroom exercises and additional resources on the topic.
LEARNING: Learning About Cryptography
A more advanced and comprehensive introduction to cryptography
Secret Code Breaker
Downloadable video clips of famous code breakers taken from history
Barcodes: Cryptography
This website, sponsored by the company, Barcodes, Inc., provides articles on a wide variety of topics related to cryptography.