Interactive
PBS

Pbs Nova: Send a Coded Message Virtual Enigma

For Students 9th - 10th
Explore the NOVA's Virtual Enigma machine used during WWII. You can send an encrypted message to a friend along with the special key needed to decipher the message. A link is also included to the Virtual Enigma.
Activity
PBS

Pbs Nova: Decipher a Coded Message

For Students 9th - 10th
The basic difference between a code and cipher is explained briefly. You can try to crack a simple cipher at this location.
Activity
Texas Instruments

Texas Instruments: Numb3 Rs: Message of the Bottle

For Teachers 9th - 10th
Based off of the hit television show NUMB3RS, this lesson is best used to serve as a preliminary introduction to coding and encryption. Messages are ciphered by single-letter substitution, and the lesson guides students into deciphering...
Activity
PBS

Nova: Secrets, Lies, and Atomic Spies

For Students 9th - 10th
The companion site to the show by the same title. Interesting site allows the reader to decipher a coded message. Information on Venona Intercepts and interviews with children of famous spies.
Lesson Plan
Shodor Education Foundation

Shodor Interactivate: Spy Game

For Teachers 9th - 10th
Learners will learn about modular arithmetic in order to decipher encrypted messages.
Article
Khan Academy

Khan Academy: Encryption, Decryption, and Cracking

For Students 9th - 10th
Julius Caesar encrypted messages two thousand years ago. By knowing the techniques of deciphering a code--frequency analysis, known text, and brute force--one can begin to understand the three key aspects of data encryption, decryption,...