Messages

9/1: The exam grading is done. Results: A: 3, B: 8, C: 9, D: 5, E: 6, F: 2.

A few comments on the exam problems:

2a. Some computed \(\gcd(x_{i+1}-x_i, n)\) instead of \(\gcd(x_{2i} - x_i, n)\), which does not work very well.

2c. Suprisingly many could not do fast modular exponentiation. Of those who could, most used straight-forward square and multiply, but some used more ad-hoc approaches - which is ok.

3b. Almost everyone knows how to add points on elliptic curves. Few people got all the calculations correct, which was as expected. Many of those who made mistakes failed to explain what they were trying to do and what results they were supposed to arrive at.

3c. Few understood that this is a straight-forward linear system of equations that can be solved like any other.

4. Few were able to solve this one. This was slightly surprising, since this was one of the example attacks on ElGamal discussed in the lectures.

5a. Surprisingly many misread the problem and solved the resulting linear equation modulo 52 instead of 53. Most of these also failed to notice that the equation does not have a unique solution in this case.

5b. Very few were able to solve this problem.

17/12: Today's exam with draft solutions.

13/12: I will be in my office Monday 16/12 from 9-13 and on Tuesday 17/12 from 9-15. You can also send me e-mail if you have any questions.

15/11: There will be no exercise class this week. On Friday, I will go through the 2006 and 2007 exams.

14/11: As announced in classs, starting Friday 15/11 I will work through the oldest exams, starting with the 2001 exam. If you have questions to any other exams, let me know and I will talk about those problems as well.

8/10: The exercise classes that are not in the computer room will be in room 822 in SBII from now on.

16/9: I will meet with the reference group Tuesday September 24. Let them know what you think about the lectures and the exercises, or let me know directly.

13/9: Note that exercise classes will be in the computer room for the next few weeks. Those who do not have access to the computer room should let me know by Monday 16/9.

13/9: I will meet with the reference group to some time between 23/9 and 27/9. Let them know what you think about the lectures and the exercises, or let me know directly.

19/8: The first exercise class will be Wednesday August 28.