I was the GSI for Cryptography, Math 195, Section 2, for Spring 2002.
A word about the homework: Be sure to show your work or explain how you got your answer. I was nice on this homework, but in the future correct but incomplete homeworks will only receive partial credit.
Also, cooperation on homework is permitted (and encouraged), but if you work together, do not take any paper away with you--in other words, you can share your thoughts (say on a blackboard), but you have to walk away with only your understanding. In particular, write the solution up on your own.
Solutions are also available by request.
Conventional Encryption Techniques (01/24/02-01/29/02)
Group Theory (01/29/02)
The Euclidean Algorithm (01/31/02)
Block Ciphers (01/31/02)
Hill Cipher, Rings, and Some Linear Algebra (02/05/02-02/07/02)
Hill Cipher (Continued): Computing the Inverse of a Matrix (02/12/02)
DES: The Feistel Cipher (02/14/02)
DES and SDES (02/19/02-02/21/02)
RSA (Continued): Computational Issues (02/28/02)
RSA (Continued): When the Exponent is Leaked (03/05/02)
Finite Fields (03/12/02-03/14/02) (Revised 03/17/02)
Finite Fields (Continued): How to Construct (03/19/02-03/21/02)
Rijndael Cipher (04/02/02-04/04/02)
Rijndael Cipher (Continued): Discussion (04/09/02)
Discrete Logarithms and Diffie-Hellman (04/11/02-04/16/02)
Discrete Logarithms (Continued) (04/18/02-04/25/02)
Elliptic Curve Cryptography (04/30/02-05/02/02)
Elliptic Curve Cryptography (Continued) (05/07/02-05/09/02)
Also, here is a note (thanks to Alex Gonzalez) concerning words whose negative is also an English word:
Words and their Negatives
Here is the policy for the other 50% of the grade. The final will be a take-home final. You will be given the exam in class on Tuesday, May 7, and it will be due on the day before the final exam, Tuesday, May 21, by 3:00. (Note: This has changed since the first announcement.) The exam will consist of two sections. The first section will consist of homework-like problems which you are to complete with no outside assistance. The problems will be include some easier computational problems, with perhaps some proofs of simple statements. The second section will consist of harder problems, of which you will choose a few (about 3) from a list of approximately ten. The problems in the second section will be some mix of more complicated computations, proofs, and discovery-research. You may work in groups of no more than 3 if you like, but only on the problems in the second section--you must complete the problems in the first section on your own. As always, if you work together, do not take any paper away with you--in other words, you can share your thoughts (say on a blackboard), but you have to walk away with only your understanding. In particular, write the solution up on your own. The final will count for 50% of your grade, along with 50% from homework.
Here are the solutions for the final exam.
Math 195 Take-Home Final Solutions
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This page was last modified on Thursday, January 23, 2003.