Teacher page for the History and Analysis of Cryptography Unit
Each layer in a system builds upon previous layers

Topic: The history of cryptography and its current applications in our society.
Michael Sirois, Lanier Middle School, Media 2000

Teachers using this lesson online:  Your current URL is
http://www.crpc.rice.edu/CRPC/GT/msirois/Lessons/crypto/teacher.html

Send your students to the URL below to get started, not to the one above.   Many of the items on this "teacher" page will give away important information that the students should discover for themselves.

Send Students Here:
http://www.crpc.rice.edu/CRPC/GT/msirois/Lessons/crypto/

Purpose: The primary purpose of the unit is to allow students to become aware of code systems and the art of cryptanalysis.

Materials: An Internet connection, WWW browser, paper, pencil.

Prior knowledge: Any knowledge students already have, regarding codebreaking or cryptographic systems, will be useful to them, but not necessary.  They should discover everything they need to know while exploring the topic.

Description: In this unit, we will learn about the history of codes, and--by analyzing and breaking down some codes into sections--we will see how they are structured. We will continue that process by inventing codes of our own, attempting to break each other's codes during the next few weeks.

Procedure: The students will examine and understand the history of cryptography to further demonstrate that each layer in a system builds on the item which precedes it.  They will come to an understanding of cryptographic systems by deconstructing coded messages, then developing their own code system.  They will also have an opportunity to enter The Edgar Allan Poe Cryptographic Challenge, and try to solve a 150 year old mystery.

Suggested URLs pertaining to lesson:  URLs for Edgar Allan Poe, cryptography, etc., are located in the students' document, assignment.html.

Note for Non-Texans:  Texas has instituted a set of guidelines for most subject areas called TEKS [Texas Essential Knowledge and Skills]..  They would be the equivalent of the items formerly referred to as Essential Elements.  They describe what the student should learn from the lesson.  The TEKS below are for the subject area of Technology.

Technology TEKS covered in this unit:
The student is expected to:

• (1-A) demonstrate knowledge and appropriate use of operating systems, software applications, and communication and networking components;
• (1-E) use technology terminology appropriate to the task;
• (3-D) identify the impact of technology applications on society through research, interviews, and personal observation;
• (3-E) demonstrate knowledge of the relevancy of technology to future careers, life-long learning, and daily living for individuals of all ages.
• (4-A) use strategies to locate and acquire desired information on LANs and WANs, including the Internet, intranet, and collaborative software;
• (6-A) determine and employ methods to evaluate the electronic information for accuracy and validity;

Length of lesson: Approximately two weeks, unit to be extended with research and project construction.

Objectives: Students will be able to

• understand the building blocks of code systems
• interpret a variety of codes
• deconstruct a cryptographic system
• know about the history of cryptography

Possible Questions Relating to Cryptography: [these questions are also on the students' assignment page]

• What if you had to deliver a message to someone, and the secrecy of the contents would guarantee your life or your livelihood or your property?  How would you make sure only the appropriate person read your note?
• What value can cryptography have for the average person?
• Is there such a thing as an unbreakable code?

The Pretest:

When students take their pretest, they should enter your e-mail address in the appropriate place, along with their own name.  Look at the pretest at this link

http://www.crpc.rice.edu/CRPC/GT/msirois/Lessons/crypto/codepretest.html

The students will link to it from their main page.  When they submit it, I'll get a copy and you'll get a copy [if they filled in the correct e-mail address].  Your copy of the e-mail should have the following:

01codemachine=Enigma
03codebreaker=Turing
04language=Navaho
05americode=never

These are the answers to the five questions on the pretest.  Be sure to check this page and the pretest page periodically.  I will expand it, eventually, to include more questions.  I'll update this page when I do.  If it will be easier for you, save the source code and devise your own version, or print a paper copy.  Be aware that the students can view the source code of a page from any browser by choosing View/Page Source from the menu.  Make sure they don't do that while they are working on the pretest [they can peek at the answers...they wouldn't do that, would they?    (8^)  ].

Below is a duplicate of the cryptogram the students have to solve to make it to the next step in the lesson.  This is the only way they can retrieve their assignment.  Your version has the answers, of course.  Theirs doesn't.

 Hx mx hx hf" u"dh z"ghjxu To go to the next section

 xc lx.y t"zzxue lx. u""s hx of your lesson, you need to

 "yrz" hf" cjt"uri" qjus"dofhitq erase the filename "index.html"

 cyxi lx.y kyxnz"ybz txgrhjxu from your browser's location

 njusxne hl," ju hf" cjt"uri" window, type in the filename

 qu"dhzh",ofhitqe hf"u ,y"zz hf" "nextstep.html", then press the

 "uh"y a"lo enter key.

Did I forget something?  ...or do you just need to talk about the lesson?  E-mail me at msirois@rice.edu

Last updated on July 25, 1999

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