Code Of The Common

Chapter Project: Invent a Secret Code

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Go to the following Web sites to find information to help you complete this project.

The Simple Substitution Cipher Web page explains the methodof transforming a message into a code.

Use the Secret Code Breaker to break the code of your letter after you've written it.

Read the story of The Adventure of the Dancing Men to learn howSherlock Holmes broke the stick figure code.


About the Chapter Project

A special sculpture stands outside the headquarters of the United States Central Intelligence Agency (CIA) in Langley,Virginia. Carved in the copper sculpture is a message in secret code. The code is so complex that for many years even CIA agents could not figure it out. The sculptor, James Sanborn, provided the secretagents with a challenge they could appreciate.

In this chapter project, you will learn about a code used by computers and write in a code used by Julius Caesar. Then, you'll invent a code of your ownand make a poster to display your code.


List of Materials:

• A large sheet of paper
• Several marking pens in different colors

Activities


Activity 1: Reading

[pic]American Standard Code for Information Interchange (ASCII) is a code used by computers. In ASCII, a number represents each English character. Use the tables below to decode the ASCII message at the right.[pic]


Activity 2: Writing

A cipher is a secret code. To decode it, you must know the key. Caesar Cipher, used by Julius Caesar, substitutes one letter for another by shifting each letter inthe alphabet three places: A becomes D, B becomes E, and so on. In Caesar Cipher, dog is written grj. Write a letter to a friend in Caesar Cipher.


Activity 3: Creating

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Codes don'talways use numbers or letters. In "The Adventure of the Dancing Men," the detective Sherlock Holmes used deductive reasoning to decipher a code that substituted stick figures for letters. Using the...