Oberlin College

Spring, 2006
Lectures: MWF 3:30 - 4:20, King 221

Cryptology

Instructor

Overview

Cryptology, the study of secret codes, serves as an excellent setting for developing quantitative problem-solving skills. Moreover, it's fun, particularly because most of the unpleasant, mechanical aspects can be handled by the computer, leaving the creative, interesting part for the you.

In this course we will tackle the problem of cryptanalysis, deciphering encoded text, using some rather tried and true mathematical techniques. To assist you are several computer programs. One is a Java program that I have developed called Krypto. The other is CAP (Cryptographic Analysis Program), which is included with the Spillman text. These program are easy to use and very helpful, but do not solve the most interesting ciphers. For that you will have to use your own reasoning skills.

We will spend the first part of the semester on "classic" cryptology, techniques used prior to the "information age" that have been rendered useless by modern computers. Later we will consider the modern techniques now employed to maintain security and authenticate documents. We will also discuss some the more colorful events in the history of cryptology.

We will use this Website for distributing material, and the handin program for submitting homework. You are be responsible for checking the Website regularly, since I will use it to communicate important information throughout the semester.

I will also use this Website for collecting references to interesting sites. If you have any candidates for this page, please let me know.

Texts

Sinkov, Elementary Cryptanalysis New Mathematical Library, 1966.
Spillman, Classical and Contemporary Cryptology, Prentice-Hall, 2005 (also available online through SafariX at reduced cost)
Singh, The Code Book, Anchor Books, 1999.

Assignments

There will be 3 to 5 written assignments. Most assignments will involve breaking codes.

Projects

During each half of the semester the class will be divided into groups. Each group is assigned to lead one class session on one of the topics shown below during each half semester. All students are expected to be prepared and participate during the group presentation. After the presentation each group will submit a short writeup describing each member's contribution.

Group membership may change after the first project.

The group areas are shown below. Clicking on a topic will open a PDF page of questions that should be answered and topics that should be included. The tentative presentation date is shown.

First half
Topic		Date (tent.)
Ancient ciphers / pecular ciphers / Mary Queen of Scots cipher		Feb 27
The Rosetta Stone		Mar 6
Babbage and Mechanical Calculators		Mar 13
Steganography		Mar 20
Second half
Topic		Date (tent.)
Station X: History of Enigma / Alan Turing		Apr 17
Other WWII Era Ciphers: Lorentz Machine & Colossus; Navajo "Wind Talkers"; Venona		Apr 24
Pretty Good Privacy		May 1
Quantum Cryptology		May 8

Exams

Midterm: Week of March 20 (online)       Final: Friday, May 19, 9:00 AM

Grading

Assignments:	55%
Projects:	20%
Midterm:	10%
Final:	15%

Late Policy

Assignments will be accepted up to 5 days late with a penalty of 10% per day. No assignment will be accepted more than 5 days late.

Decorum

Class will begin promptly at 3:30. No one will be admitted to the room after 3:35. If you leave after 3:35 and before the end of class, you will not be re-admitted.

Honor System

All graded work is subject to the Honor System, as described at http://www.oberlin.edu/students/links-life/rules-regs05/06honor_code.pdf

Icons provided by