arminstraub.com

Spring 2017: Cryptography (Math 481/581)

Overview

Instructor Dr. Armin Straub
ILB 313
straub@southalabama.edu
(251) 460-7262 (please use e-mail whenever possible)
Office hours MW, 9:05-1:15pm, or by appointment
Lecture MWF, 1:25-2:15pm, in ILB 465.
Midterm exams The tentative dates for our two midterm exams are:
Wednesday, February 22
Wednesday, April 5
Final exam Wednesday, May 3 — 1:00-3:00pm
Text Introduction to Cryptography with Coding Theory
by Wade Trappe and Lawrence C. Washington (Prentice Hall, 2nd Ed., 2006)
Online grades USAonline
Syllabus syllabus.pdf

Lecture sketches and homework

To help you study for this class, I am posting lecture sketches. These are not a substitute for your personal lecture notes or coming to class (for instance, lots of details and motivation are not included in the sketches). I hope that they are useful to you for revisiting the material and for preparing for exams.

After most classes, homework is assigned and posted below. This homework will not be collected; instead, it helps you prepare for the quizzes (which will usually be similar to the assigned homework) and our exams.

Date Sketch Homework
01/09 lecture01.pdf finish Example 6 and do Example 7; also review any topic discussed today which you don't recall fully
01/11 lecture02.pdf do Examples 9 and 10; also checkout Example 13 as a bonus challenge
send me an email before Friday if you can crack the message
01/13 lecture03.pdf do Examples 16, 19 and 22; also checkout Example 23 as a bonus challenge
send me an email before Wednesday if you crack the code
01/18 lecture04.pdf do Examples 29, 31 and 32; also checkout Example 30 as a bonus challenge
send me an email before Friday if you can solve the bonus
01/20 lecture05.pdf do Example 42; prepare for Wednesday quiz
the quiz will have three problems: inverting modulo n (generalized Euclidean algorithm), computing powers modulo n (Euler's theorem, followed by binary exponentiation), expressing numbers in different bases
01/23 lecture06.pdf review basic number theory for quiz; also checkout Example 43 as a bonus challenge
send me an email before next Monday if you can solve the bonus
01/25 lecture07.pdf do Example 55; also checkout Example 54 as a bonus challenge
send me an email before next Monday if you can solve the bonus
01/27 lecture08.pdf do Examples 58, 59 and 60
01/30 lecture09.pdf do Examples 62 and 64
02/01 lecture10.pdf do Example 69; prepare for Friday quiz
The quiz will be similar to Example 64 (probably using 4 instead of 3 bits).
02/03 lecture11.pdf checkout Example 72 as a bonus challenge
send me an email before next Wednesday if you can solve the bonus
02/06 lecture12.pdf do Examples 79 and 80; checkout Example 76 as a bonus challenge
send me an email before next Wednesday if you can solve the bonus
02/08 lecture13.pdf do Examples 86, 88 and 89
We will have a quiz on Monday covering the Chinese remainder theorem. More details Friday.
02/10 lecture14.pdf do Example 91; finish Example 96
The quiz on Monday will be similar to Examples 80,86,89.
02/13 lecture15.pdf do Example 99; finish Example 98; think about Example 100; review quiz
02/15 lecture16.pdf do Examples 102 and 103; start preparing for our first midterm exam next Wednesday:
midterm01-practice-lecture.pdf (these are problems we discussed in class)
02/17 lecture17.pdf do Example 108; continue preparing for the midterm:
midterm01-practice.pdf, midterm01-practice-solution.pdf
02/20 review get ready for the midterm!
02/24 lecture18.pdf review the midterm (solutions posted below); checkout Example 114 as a bonus challenge
send me an email before next Friday if you can solve the bonus
02/27 lecture19.pdf finish Example 117; checkout Example 116 as a bonus challenge; enjoy Mardi Gras!
send me an email before next week Wednesday if you can solve the bonus

Sage

For more involved calculations, we will explore the open-source free computer algebra system Sage.

If you just want to run a handful quick computations (without saving your work), you can use the text box below.

An easy way to use Sage more seriously is by creating an account at http://cloud.sagemath.com. This free cloud service does not require you to install anything, and you can access your files and computations from any computer as long as you have internet. To do computations, once you are logged in and inside a project, you will need to create a "Sage notebook" as a new file.

Quizzes and solutions

  1. quiz01.pdf, quiz01-solution.pdf
  2. quiz02.pdf, quiz02-solution.pdf
  3. quiz03.pdf, quiz03-solution.pdf

Exams and practice material

There will be two in-class midterm exams and a comprehensive final exam. Notes, books, calculators or computers are not allowed during any of the exams.

Our tentative exam schedule is:

The following material will help you prepare for the exams.

Last change: 2017/02/27
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