Chris Christensen

Professor of Mathematics
Department of Mathematics
Northern Kentucky University
Highland Heights
, KY 41099

FAX: 859-572-6097


CSC/MAT 483 - 001

This class meets MWF 12:00 – 12:50 in ST 254.

Spring 2010


Amber Roger’s vbreaker.

Student-produced materials from previous classes

CrypTool  (go to links and projects)


Here is a copy of the syllabus for CSC/MAT 483 – 001.

Here is a copy of the Departmental syllabus that applies to all MAT and STA courses.


Monday, January 11

Simple substitution ciphers

            Hints for solving cryptograms.

Wednesday, January 13 and Friday, January 15

            Class did not meet.

Monday, January18


Wednesday, January 20

            Kerckhoffs' principles

            Caesar ciphers

Friday, January 22

Monday, January 25

            Multiplicative ciphers

Wednesday, January 27

            Affine ciphers

            312 affine encryptions of THE

Friday, January 29

            Keyword ciphers

Monday, February 1

Wednesday, February 3

Friday, February 5

            Playfair cipher

Monday, February 8 and Wednesday, February 10

            Some old, long, and wordy notes about Hill cipher.

            A less wordy Introduction to the Hill cipher.

Friday, February 12

            The two Hill cipher known plaintext attacks that were done in class.

Monday, February 15

            NKU closed because of weather.

Wednesday, February 17

            Test one

            Vigenere cipher cryptography

Friday, February 19

            Vigenere cryptanalysis

            Friedman's index of coincidence

            Another way to find the length of the keyword

Change test one problem number 7 to:


7a.  If a message is first encrypted with an affine cipher with multiplicative key 7 and additive key 12 and then encrypted again with an affine cipher having multiplicative key 15 and additive key 6, what type of cipher is the composition?  What is the key?


7b.  A ciphertext is known to have been encrypted with an affine cipher.  Using frequency analysis, it seems that plaintext e is ciphertext C and plaintext t is ciphertext H.  If these assumptions are correct, what is the key?



Monday, February 22


Wednesday, February 24


            Gronsfeld and Beaufort ciphers


            Introduction to Enigma


Friday, February 26


            Stream ciphers


            One time pads and stream ciphers


Monday, March 1


Picture of the US-soviet Union hotline


About spy number stations



Wednesday, March 3


            Baudot code


            Character addition table


Friday, March 5


            Transposition ciphers  See columnar transposition pp. 5 – 11.


Spring Break


            UC 031110

            UC 031110


Handbooks of Cryptography link to Handbook of Applied Cryptography by Menezes, van Oorschot, and Vanstone.


Applied Cryptography by Bruce Schneier.


Monday, March 15 and Wednesday, March 17


            Simplified DES encryption example.


            Simplified DES algorithm from Trappe and Washington.

DES algorithm  from Schneier’s Applied Cryptography

Friday, March 19


            Test two


Monday, March 22


            Finding multiplicative inverses


Wednesday, March 24


            Introduction to finite fields, I


Friday, March 26


            Introduction to finite fields, II


Monday, March 29


            Simplified IDEA algorithm by Nick Hoffman


Wednesday, March 31


            Simplified AES


            Algebraic cryptanalysis of S-AES by Sean Simmons


Friday, April 2




            The introduction to this paper introduces common symmetric key block ciphers


Monday, April 5


            KeeLoq cipher


Wednesday, April 7


            Block cipher modes


Friday, April 9


            Test three


            Classification of the SHA3 candidates


Monday, April 12


            Cryptographic hash functions


Wednesday, April 14


            Internet timeline


            Diffie-Hellman paper


Friday, April 16 and Monday, April 19 and Friday, April 22


            Diffie-Hellman key exchange


            Introduction to public key cryptography


Wednesday, April 21


            Presentation by Jintai Ding


Friday, April 23


            El Gamal


Here is a copy of the comprehensive exam.


Monday, April 26


            Introduction to RSA




            The article in Scientific American that introduced RSA. 


Wednesday, April 28


            Presentation by Nick Hoffman


Friday, April 30


            The Case for Elliptic Curve Cryptography


            certicom ECC tutorial











KYMAA Torres


KYMAA Ramping Up