PBS
Pbs Nova: Decipher a Coded Message
The basic difference between a code and cipher is explained briefly. You can try to crack a simple cipher at this location.
Texas Instruments
Texas Instruments: Numb3 Rs: Message of the Bottle
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...
PBS
Nova: Secrets, Lies, and Atomic Spies
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.
Khan Academy
Khan Academy: Encryption, Decryption, and Cracking
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,...